Last month I think the highest amount i've seen was 0.1 mbtc but I still took the cashback and I remember there was an instance where the cashback was higher than the other rewards.
I tried slots a long time ago I think and didn't really enjoy it. I find that most forum people who bet on dice (which is the ones I knew the most before Sportsbet) all don't really play slots, I feel like maybe it's something very different as an appetite for sports people also.
So yes, at the moment I guess I am going to switch a lot more to cashback now just to "save" myself some money