Wanted to share an anecdote (I hope that's OK). I jumped to Linux on my gaming pc last August (Bazzite) and I've been having a blast. Almost everything works either out of the box or with a minor tweak (the tweak being updating Proton). But I am the sole linux user in my D&D/gaming group, so obviously this is the source of some of our banter.
Last night, we decided to play some Valheim. Bought it before switching to Linux and never tried it, so steam had to install some compatibilty stuff. But once everything was installed, it too worked like a charm (surprise surprise). We were having fun, sailing around on our ~~crappy raft~~ mighty longship and striking a nice pose while doing so. I decided to take a screenshot, but didn't know if there was a keybind to disable the HUD, so I asked the two more experienced Valheimers with whom I was playing. Neither of them knew it by heart, but one of them looked it up. He said: "It should be Ctrl + F3". I tried it and it didn't work for me, but it did for him. "Wow, imagine playing on linux where nothing works" our other friend chimed in (jokely, don't worry). Our first, more helpful friend said: "Maybe try Ctrl + Alt + F3?" So I did. Then, my whole computer froze, just as we landed on the edge of a dark forest with our raft. I thought: Oh fuck what did I do this time. Pressing again didn't help, but after about 20/30 seconds, I was greeted with a shell login. Now I could hear my friends and the game in the background again, and they could hear me, but all I saw was a shell. I decided to log in, and still only got a shell. So, as my friends were frantically fighting a skeleton, I was searching for what on earth happened, and, more importantly, how to fix it.
Thankfully, I wasn't the first idiot to start pressing random buttons on their Linux system, and someone had this exact issue years back as well. I had a quick read, and learned that apparently the Ctrl + Alt + Fx buttons switch between virtual terminals. The post on the Ubuntu forums mentioned needing to switch to terminal 7 (Ctrl + Alt + F7), which also didn't work. But trying the other buttons, I found that the desktop environment is on terminal 2 (at least on Bazzite/Fedora).
And the funny thing here is that, even though I was essentially gone for a full minute, maybe a minute and a half, my character was fine, my Linux naysayer friend had died to a skeleton, and I had learned something new about our great OS :)
Oh I not bashing on the feature, don't worry. I was just very surprised when my computer seemed to freeze XD.
Out of curiousity, what kind of use cases do/did they have?
When you get a moment, you could try switching over to the tty again, login to the shell, and then try typing in the command
btop(which I think is the Bazzite specific version of the default "top" command, and should be installed by default). Top is basically a task manager, and you can see what programs are running (and taking up resources) right there in the terminal. If your system freezes up, you can often unfreeze it by killing the unresponsive programs. It's probably useful to familiarise yourself with that interface before you need it.Well, as an example, when nvidia next demonstrates that one of the biggest companies on the face of planet Earth just cannot possibly afford to hire a couple of more developers to maintain their drivers and keep up with Kernel development and your Window Manager consequently fails to run, a TTY is nice for downgrading the drivers to a version that actually works. :)
When your entire desktop environment freezes, on Windows you'd have to do a hard shutdown, risking data loss or corruption.
On Linux you switch to another TTY, kill the process that's locking up everything, and go back to work.
Troubleshooting and fixing your system when your desktop environment is broken
You don't need a desktop for a server. A local TTY allows the same stuff as connecting over SSH but you can do whatever you need to bring up the network. The drawback is having to go to the data centre...