A lot of people say that you can use 1-3* just fine and yes, they're right. You can indeed use low stars in this games. But the thing is, I don't play this game for the gameplay necessarily. It's not bad, and I actually think it can be quite fun. When I play FGO, though, I (unfortunately for me I suppose?) want to use the servants I like. Not servants that I don't like (which include the vast majority of low stars).

basically this. i would've quit this game almost 4 years ago in the event i failed to get the servant which i was drawn to this game for.

i'm here to have fun with fate/ characters i like; gameplay to me is only bonus.