Pick Intent is helpful, but not in the way you are thinking!
The information gained from pick intent abuse is so valuable that it offsets the disadvantages of pissing off your team.
You can stop your team mate from picking a disaster pick.
That is one of the most obvious benefits of banning your own teams pick intent, but the real benefit to banning your own teams intent is the next one.
It serves as a litmus test for toxicity and maturity.
If I ban my own teams champ and they start raging hard then I know they are a toxic player before the game even starts and can make my decision at that point rather than being stuck 30+ minutes with them.
If they instead move on without raging and pick something else, then I know that person is more emotionally stable and is probably going to be a good team member. It makes me feel bad for banning their pick at that point but the knowledge gained was worth the price.
Ever since I've started doing this every game and then dodging if a toxic shitter was revealed, my winrate has gone up by about 10%.