I don't feel comfortable with them having my banking login. If they get hacked they can do a lot more damage with that
Another point on these banking accounts, you’re not worried about the points expiring, and you’re likely signing into your account at least once a month (so you know around how many points you have).
Airline and hotel points on the other hand, you’re likely not signing into them nearly as often, so it’s more susceptible to expiration.