Steam Deck is based on Arch Linux & folks are trying to get as close as possible on their other PCs I assume.

I daily manjaro, what's wrong with it?

I used it for a while, never had an issue. im on base arch now but ngl manjaro had the best gnome implementation I've ever seen

After having distro hopped for over 10 years ive settled on manjaro xfce and been happily running it for roughly five years now. It works very well out of the box, comes with working support for nvidia and steam being preinstalled. It strikes a very good balance between latest bleeding edge and just works, a position where it is bound to sometimes make some mistakes. But I've never noticed any issues. I can fully recommend it, it seems like most people that give it hate comes from memes or have never tried it themselves

I use Manjaro, what's the problem?

It was an often-recommended distro a couple of years ago. When SteamOS 3 was on the horizon, some people recommended it as probably the closest to SteamOS 3 on the market. Now, I haven’t bothered uninstalling it on my old computer yet.

People who Googled arch linux for dummies and realized even that was too complicated and then proceeded to install an arch based distro just to get AUR.