It means nothing. Experiencing a bunch of events should effect your personality, your character, your desires, you reasons for doing things - all of which are roleplaying attributes, not stats. Levels are likewise. Every player in an RPG should be relatively the same. Since everyone will choose different levels for their basic attributes the variety in the players will already exist.
Some people are smarter and others are stronger.
The player chooses this at character creation. Players should also have to choose strengths and weaknesses. These are the things that enhance roleplaying. Ah, there's the rub. Characters must grow in some fashion for the immersion of a player into a game world.