Steam Deck apps (mostly) have to come from a Flatpak repo to install correctly but Flathub (the default repo and therefore defacto app store on the Steam Deck) has lots of the common apps for daily use, even if they are largely unofficial/unsupported versions. So for 95% of people, it's definitely usable as a laptop/desktop replacement, but if you want to develop or want stuff outside the Flatpak repos, it's a bit of a hassle.
That said, I love this thing.
If you want a portable DevOps station, you want a cheap laptop. You don't want to use the default Steam Deck keyboard for much more than entering a login name or something. A Steam Deck with a keyboard plugged into it is much closer to a desktop setup than anything I'd call portable.
But portability is the only question. It's still a full computer. It just isn't a very convenient one for anything other than games.
I personally do use it a lot like a Nintendo Switch, though. You can easily have a desktop-like setup at home behind a dock, and then pop it out and carry it off portably. It's not quite as slick as a Switch but it works. But, again, this is a desktop setup with the Deck standing in as the computer, not a portable setup.
Loving the trend, though. Between Distrobox and Docker, containers seem to be the inescapable "Matryoshka dolls" of the tech world.
But all jokes aside, the flexibility this provides is impressive. If you told me a few years ago that I'd be able to run a full Ubuntu environment on a handheld gaming device, I would've raised an eyebrow