What is wrong is when people expect too much from deposit bonus or when people think that they are on +EV by taking deposit bonus.
Yeah, most of the time when the marketing of the casino is too good, as someone who was attracted by the numbers given, they just eventually deposit or register to get the deposit bonus without knowing they need to achieve a pile of requirements for them to be qualified then just to get disappointed and feel cheated once they contact the support or reread the bonus terms lol.
Because maybe they think with a deposit bonus can be withdrawn easily if they win in the bet ... even though we know so many stacks of betting requirements to fulfill it.
Arhh I never took part of the deposit bonus because I knew it would be difficult to win.
Even if it's 300% first deposit bonus.

For pro gamblers, a deposit bonus is a big trap so I am not surprised that you said you won't consider even a 300% bonus as a deposit offer same with me also, no matter the amount of the deposit bonuses that are offered, I don't consider them rather I focus on gambling with my available fund.
Trying to meet up with bonuses requirements is a pain in the ass of many and we should try by all means to avoid falling into that trap whenever we come across such offers.
If people say deposit bonus is a big trap, they are not eligible to be called as pro gambler. Simply because pro gamblers should know about deposit bonuses better than beginners so they can decide better whether to take the bonus or not. Those who consider deposit bonus as a trap are those who do not understand it well, or do not even read the whole terms behind the bonus. If gamblers understand it well and if they take it means that they are ready for all the consequences including the wagering requirement as the hardest part to complete.