My thoughts exactly. Randomised booster packs are basically a kind of gambling. And I know from experience that they can be addictive.

But if gambling should be banned, why are lotteries still allowed? They are arguably the worst kind of gambling.

Gambling is not banned in Belgium, it is regulated. There is a state-owned lottery, plenty of casino's, sportsbetting companies etc. One thing that is banned is selling gambling products to minors.

You are right that booster-pack based collectible card games are basically gambling (and they are definitely also targeting minors). However, there is also a significant difference between a game that front-loads this gambling (you know what you are getting into, and you buy and construct your card deck before a game) and a game that tacks it on an existing game. It a gray zone if the loot box contents offer no in-game advantage (e.g. Valve sticks to purely cosmetic items for their games), but is pretty sinister from both the game design and ethical perspective if it offers an edge in the game. It's back-loaded gambling, where a pay-gamble-to-win scenario is dangled in front of the player after getting killed in a shooter.

Depending on what you mean then booster packs will usually be pretty clear in what you get, loot boxes do not

Edit: I see now you mean randomised ones, and I wholly agree with you