There are some players that are very good at taking HBP. Coaches probably do watch for that.
My son was a pitcher and a very good hitter in HS. I was never nervous when he went up to bat. If he hit 4 times out of 10 at bats, thats 400 avg. 4 good outings out of 10 for a pitcher wont get anyone a job. Seeing it from both sides, hands down its rough being a pitchers parent.
The reason why they say that baseball is a game of failure, is because for both hitters and pitchers you dont get better at your game if you have never experienced failure, and a lot of that happens for everyone in this game.
Its how you overcome your failures that make you successful or not successful.