Buy potion, skip content and lvls.
Skip cutscenes.
Suddenly find yourself in Stormblood areas.
You don't understand a thing of what's happening and what those colored boxes do on your skill bar.
Skip 4.X cutscenes cause you don't understand a thing of what they talk about.
Be a terrible player in dungeons.
Complain that the community is toxic or that the game has no content.

I understand that some people want to pay money to just pew pew mobs but I'm afraid those skip potions will have some disastrous side effects.