This is a very valid subject to discuss.
Belguim is just one minor case. This particular act was nearly passed in US and EU and in Japan it is also enforced because Loot Boxes or 'Gacha' systems are in place in a lot of games.
It became a prominent issue with Star Wars Battlefront abused micro transactions. It should be noted a lot of Japanese Mobile Games actually do list the % rate of drops from a Gacha base system with loot boxes.
Likewise Lootboxes in a game like Overwatch or Fortnite would have color coding.
In general a Loot Box or Gacha system will be broken down into Common, Rare, Super Rare and SSR (Specially Special Rare) comes into play usually with a 1 star to 5 star system.
Normally the rate for a SSR would be 1% in the prize pool and then during a rate up it could got up to 4%
Sometimes they break it up so there is a Free Gacha system where you can use ingame currency farmed in the game or a paid currency and a paid for banner or loot box that gives higher results or anything from Rare Upwards and a rate up.
However this still doesn't solve the core issue with the Lootbox/Gacha system and that's kids who get addicted to rolling for a SR or SSR item. Most games, particually on mobile will have a $80 price tag on their biggest bundle which will give the player a suffienct amount of currency to roll with. Arguably if a Parent doesn't look after their child and control what they play and spend money on, then that in itself is bad parenting.
But as this issue continues to grow, governments around the world are taking this a bit more seriously as gaming has gone somewhat unchecked.