Many people who want to try out the game benefit greatly from trying the demo variant first. I don't know how that works with exact values.
ya.ya.yo!
They just said that casinos can configure the RTP of demo play of slots. Doing so, expect to hit a lot than the real money play. I usually play demo if I want to be familiar to the slot, or sometimes just for fun, and when thinking for how should I play the slot. Just observing how the slot will go on what ifs.