Morse code (aka continuous wave/CW) is in very common use in amateur (ham) radio, predominantly in CW Contesting [0], DXing, and low power (QRP) and portable operations (like parks on the air/POTA, summits on the air/SOTA [1]) as CW an extremely robust, efficient modulation.

In other words, a 5w CW signal is roughly equivalent to a 100w voice signal -- more miles per watt. Plus you can fit a lot of signals in less spectrum. It's slower than voice or data modes but you don't need to say much to exchange enough information for a valid contact. And learning Morse code is just fun and a superb mental exercise; amateur radio enables Morse code to be actually useful and enjoyable in the modern era.

It's also used for:

* amateur radio direction finding/ARDF (radio orienteering) [2]

* High speed CW competitions (which used to be much more popular in Eastern Europe) [3]

* automatic identification of radio beacons and repeaters (e.g. aviation Navaids like NDBs and VOR, EMS/fire/police/business radios)

* backup/emergency communications for governments & armed forces

[0] https://www.youtube.com/results?search_query=cw+contest. Also https://www.youtube.com/watch?v=JgnEGSLeedg - the radio displays a spectrum waterfall in which you can see dozens of CW signals.

[1] https://www.youtube.com/results?search_query=parks+on+the+ai...

[2] https://www.youtube.com/watch?v=I9H8irEMnf4

[3] https://www.youtube.com/results?search_query=high+speed+cw+

clarification: CW is a modulation type, on which Morse code is encoded using an on/off carrier wave. Much like how Amplitude Modulation/AM is a modulation on which voice is encoded by changing the amplitude of the carrier wave.

About ten years ago I set custom vibrations for my top contacts on my phone to be the Morse code representation of their initials. Ever since, I’ve had the super power of knowing who is texting or calling me without pulling out my phone. I’d say that alone has made a quick memorization of the alphabet worth it.

Plenty of use today in amateur radio, especially amongst QRPers (low power enthusiasts, signals <= 5 watts). It's easy to build transmitters/receivers for, and it's more efficient than, say, voice modes like SSB in terms of spectrum usage and how far you can get per watt.

In aviation, VOR stations broadcast their identifier in morse (so you can confirm it's the right station) but VOR is being killed off in favor of GPS.

Practical applications include:

1. communicating with other prisoners

2. communicating with the team trying to rescue you in your sunk submarine

3. any place where you're trapped but can bang on something

4. keeping your comms secret because nobody will even know you're using morse

5. secretly communicating with others during class (I knew two sisters in high school who would jibber jabber all through class by signing letters with their hands under the desks).

6. blinking in Morse when the terrorists put you under the TV cameras for your confession

7. your radio setup can only do on/off

8. you cannot remember how smoke signals worked

9. you need to flash a lamp at the airplane who might rescue you

And so on.

There has been a bit of a revival in CW since the pandemic in ham radio. Lots of hams took the time to finally learn it with the extra free time they had. So as far as amateur radio goes, it’s more popular now than it has been in a long time.

Morse code is alive and well, especially during contests where efficiency means performance. There are a few reasons:

It has high spectral efficiency; a CW transmission is only a few Hertz wide on the spectrum, whereas even SSB voice needs several kHz. This lets you use very narrow receive filters, to cut out adjacent noise and make contacts in difficult conditions.

It can achieve useful communication at very low power, with very simple equipment. Look up "qrp cw kit" and you can get $15 transmitters that you solder together from parts in a few minutes, and these aren't VLSI parts like some wifi chip or whatever, these are single discrete components. Hams love hand-built equipment, or at least the theoretical ability to use hand-built equipment, and QRP (low-power operation) is a hugely popular challenge.

It occupies a sweet spot where it's simple enough to encode by hand and decode by ear, but also easy enough for computers to operate. So there's a wide range of automation available, from whole-band decoders to keyboard-interactive QSOs, or you can go completely bare-handed if you prefer. That makes it appeal to more people than a more modern computer-required mode like PSK31 or FT8. (Those have even higher spectral efficiency, though, so they're popular in their own way.)

Out of curiosity, what does the CQ in your username refer to?

A nice thing with CW is that you can get it through some really impressive noise floors. I personally never use it outside of contesting though and that barely counts since it tends to be macros.

Also, all amateur stations are required to identify regularly. Relays will ident quietly in morse so it doesn't interrupt the voice comms happening on that channel.

Last year I was running a semaphore lamp off my fire escape

https://www.youtube.com/watch?v=OPE8xHSIaKk

It works great for zero dimensional displays that are far away in brought daylight. For example, the Chaos Computer Club used to hack some rental bikes which had an LED that indicated whether the bike was available or not and the hacked bikes would flash "CCC" in morse code, so you could easily identify the hacked bikes from a distance.

I'm not sure about audio morse though, I'd guess voice would be better in all cases there.