They are a business at the end of the day and this is just a clever tactic to ensure that their customers quickly complete their level 2 KYC verification since they have no shortage of money basically.
It's a mutually beneficial tactic, but it sucks to see more and more proper crypto gambling sites become centralised in this manner which we all knew was coming.
They clearly planned this carefully before deciding to give $250 per selected user... it’s a significant amount, especially considering the large number of users. Stake, being one of the most popular casinos and sportsbooks, has a massive base of gamblers. Offering $250 is reserved for loyal gamblers who’ve spent considerable time and money on the platform, in other words, those who’ve helped make the casino more profitable.
From what I’ve read, this bonus isn’t offered to everyone. It’s invitation-only, making it a reward for the most dedicated players.