Yeah that kind of thing makes sense when they offer decent bonus terms(ie 30-35x wager) but stakemania etc is 45x d+b wager and generally 3x deposit winnings cap) so they will win almost every time, I doubt they would really care if every single one of your deposits claimed a 200% bonus etc because they are doing really well out of it.
iirc it's pretty common I have 2-4 200%+ offers on my profile at any time when you get to their lowest tier of VIP.