>Should we in-game purchases for those in-game items too, under the premise that purchasing them is unbounded, unhealthy and addictive?

I think that the premise is a little weaker for straight up purchases because the uncertainty associated with gambling is what makes it so exciting, but yes if we would observe that a lots of children or families are unable to manage their finances and that this negatively impacts the financial behaviour of especially young adults, sure I don't see any problem with regulating them and limiting the use of those mechanisms in videogames.