It's true. Every gambling sites really needs a promotions to attract more players and play on their sites, that is why they are starting great bonuses that will attract new players. Every gamblers really finds gambling sites that has a promotion for them to have a good benefit to it. Right now, I am also playing in a bitcoin casino that you have also mentioned which is vegascasino.io it is a trustworthy site who also offers great bonuses especially for new players that they can get 225% on deposits and get up to 1,000 mBTC, that is why i started to play on this site for me to have a good benefit too. It is safe to play here and it has quick deposits and withdrawals that makes me convenient play here.
Yes i totally agree with you. Every site should have promotions some way or another. For example, it could be only temporary promotions sometimes during certain times of the year to encourage more demand, that could totally work.
Because they biggest concern from my point of view is getting new clients then maintaining the ones they have happy when it comes to promotions. And the possibilities to do so are a lot but those bonus in deposits are a no brainer from my point of view because it definitely encourages more to play.