[quote=LukasPrism]
Advantage does have everything to do with rerolling in 5e, but what I'm understanding from you guys is that for some reason this was never part of the dice rolling process players can do in the game.
I feel hoodwinked. They definitely need to change this.
Advantage and re-rolling are quite different things in 5E, as explained by mrfuji3. The fact that you have them confused is exactly why Larian needs to explain these concepts better.
There are cases where you can roll with advantage/disadvantage AND do a re-roll, which is why this needs to be cleared up.