I use a deck to control robots at a theme park.

I use it as a general purpose computer. I set up an encrypted home partition by more or less following this guide: https://github.com/hirak99/steam_deck_encryption. I have a bag that nicely fits the deck, charging cable, dock, and a 60% keyboard for travel.

My friend screenshares shows with me and we watch and talk to help me fall asleep at night ❤️ It works better on the deck than my phone

I use it as my primary PC! It's such an awesome and stable Linux experience

Ukrainians using it to control machine gun, so they dont have to expose themselves in trench warfare.

I have it connected to my TV so I can stream sports.

I use it for 3D modeling using a BT keyboard and a drawing tablet. Works great with Blender and FreeCAD both.

I also use it as a regular old PC. I work from home (design, illustration), and do all of it on a Deck plugged into a dock.

Mine spends a lot of time docked to the television so I can torrent/stream things.

Though I have yet to get a Deck for myself, I'd probably use it a lot to read comics. Having used the Vita a lot for that, being able to control the comics with a physical controller was fantastic, and the far greater processing power of the Deck should also avoid pages taking a long while to load (loading Humble Bundle's ebooks in measly 512 MB of RAM is an experience).

Pron...

Basically everything. It's my only PC right now.

I use mine to run VJ software and do light shows at music events.
Since the deck is a powerful computer, and the form factor is quite compact, I find it better than laptops for the task.

I connect it to my projector to watch content.

Producing audiobooks

Used mine as my main PC for half a year, doing everything from gaming (duh) to embedded development. Used RWFUS to install packages not available on flathub, but have recently started experimenting with the NIX package manager (I'm still running write-protected SteamOS).

My sister uses hers as a test and development machine for linux and Android applications.

Thought about using my SD in my model aircraft hobby, but never got around to that. Maybe I'll use it when playing around with my car with the OBD2 adapter, since i can easily connect to it from my current main rig.

I watch movies and TV shows with Kodi

Streaming video to a TV

Mostly decking about.

I temporarily used it as a computer (mostly just firefox tbh) when my main computer was out of order, normally no.

Last Weekend I installed GNU Octave in Desktop Mode to plot a mathematical curve

When I am travelling I use the deck and dock to order product (Libra office), Email, checking credentials of staff and watch video.

Only issue I have is the stupid jumping of frames when watching video in firefox due to not knowing how to turn of the stupid "smoothing" crap.

Closest I've come is accessing the browser on desktop mode to transfer files (pretty much just games or files for games) and soon I hope to add custom boot videos. Otherwise, it's just a game player/emulator player for me.

Random question, but does anyone know a way to make it so only custom boot videos play when you select random or have we not gotten that far yet?