Bit question and kinda ethics?

Hello! I have been riding about 7 years ( I am on the come up from quitting 2 years ago) I am currently riding a new lesson horse with my trainer. This horse is super sweet and kind on the ground. When I would ride him in his old a bit (a straight bar with a roller as I recall) He hated that bit and i would do every trick in the book to get him to stop he would ignore the bit and keep going. Also when bridling he would fight the bit and it got to the point where my trainer would have to bridle him. My trainer noticed this and started using different bits on him before they landed on a twisted snaffle (the twist is a small twist). He seems to really like this bit. He doesn’t fight trying to bridle and hes much more responsive and listens to rein aids better. I do tend to ride in looser reins and use a lot more leg due to my previous riding experience with Tennessee walking horses and this horse is trotting horse (some form of draft cross i believe if thats any help at all) I do understand the mechanics of twisted bits, how they work, and that are pretty split topic I’ve seen. I wanted some online feedback seeing if I should be worried or not for him because he’s a great horse truly and I don’t want to hurt him or cause him pain.