It will depend on the game. Though, it will play games that the PS5 won't so that is part of the pull I think. It is likely you can build a better computer yourself if you know how Legos work since building a computer is almost that easy now.
At this point the most expensive stuff is basically RAM/HDD(SSD).
For some people this is probably a good jump into PC gaming in the living room. To the people that already are PC gamers and know how to build their own stuff this is very expensive (especially if you are willing to look at used hardware).
Oh, you can also use it as a normal computer too if you want. You can't do that with a PS5. It will let you connect damn near anything to it over USB/etc so that could matter to some people. If you hate SteamOS you can install something else or you can cringe put windows on it too.