As this person has said it pretty much how it gets looked at. I been in plenty of guilds that do prize stuff with in game currency etc, as long as it isn’t advertised not much comes of it.
tourney and stuff are as long as the prize is from the person hosting and people partaking do not have to buy in as he said. However again it you can not advertise within the game you can promote or whatever it in your discord, guild, stream etc, you just cant go around chat and trade chat advertising your event with cash money prizes. Betting is a whole different beast regardless of where you do as there are many laws depending where you live about online gambling for real life currency.