I feel you. But to be honest, most if not all casinos credit the winnings from free spins to the player's bonus balance not the real balance and he can't withdraw it without meeting the wagering requirements. However, they had to make this clear from the beginning so you can decide whether to complete the task or ignore it.
Also, since this is a reward for completing a task (filling out a survey) they had to lower the wagering requirements (40× is too much). And I don't understand why they made the bonus valid for just three days and why you have to play specific games?
Well, if they're gonna ask for feedback, they should be more transparent; they weren't until the "reward" was sent to my email in which I found out was the free spins.
I mean I understand rewards are small and all, and I'm totally fine with that even with just like several thousand Sats but it's simply an insult to give free spins that most of us won't be able to achieve the wagering target without losing them all.
I'd expect it to be directly credited into my BTC balance instead of being provided as a locked bonus.
Exactly. Bait and switch.