You will have to keep your Store install if you want to link your existing account to Steam unless you want to start over. Then you willl be able to remove it once it's done.
Converse with fellow players
I don't know why Microsoft used the store for this. Even their other softwares like Office avoids it.
I don't have any issues with a Tweaker fresh install. But you have to start fresh and mostly ignore the Windows Store.