I suspect the reality is that preventing illegal gambling via enforcement would be basically impossible to do effectively without spending a significant portion of the police budget on it. Allowing heavily regulated legal gambling is more like the lesser of two evils.
I’m curious why you think that. There will always be illegal casinos, but the interest in slot machines would surely not be large enough to reach prohibition level behaviours?
But I’m also unsure how I feel about prohibiting a behaviour, given the whole slippery slope article etc
It'd still be run illegally - I'm sure in Queensland there were illegal casinos in pub districts before pokies were legalised in the... 1980s I want to say (or maybe early 1990s). They probably offered gambling on credit and other stuff that is now illegal (not to say it still doesn't happen but it'd be very uncommon).