how good is banning items?

so i've been playing for a bit now, and unlocked the possibility of banning items, but, is it worth it to ban? every round you get 12-13 gold, a ban is 1 and gets more expensive every time, i feel like banning an item from the pool doesn't shrink it enough to get better shop consistency. The fact that there are so many general items which are trash for the most part fucked up a lot of rounds for me, but banning them didn't make it better, at least for me, i still can't ever find a necessary item until late mid game. Do i need to improve my minmaxing in any way? i always see people have really expensive loadouts in this thread and can't ever understand how do y'all manage to get all that stuff in just 15 rounds with funds that limited.