Domain spam with casino anchors

Are these still usable for betting sites? Their previous niche are non-betting/casino though.

Sounds like a third/fourth/fifth/etc-hand domain, previously expired and then attempted to be repurposed for casino promotion. If the last owner has let it expire, it's probably because the domain didn't work out for them. I suppose you could try using it as a buffer for other casino/gambling projects, but I wouldn't bother trying to resurrect it as a main site.