Quote Originally Posted by Kyutaru View Post
No, why would it? Do you have an alternate method of doing the same task that functions better and simpler than XP? Video games use it for the same purpose, discouraging players from going back to old zones with weak enemies and effortlessly racking up progression strength. Often you can do this to some extent for farming if higher enemies are too strong for your team but it's much less efficient and grindy, promoting again the idea that taking on stronger challenges is worthwhile while not completely isolating players who are unable to do so. Similarly, if Crafting gives XP, the game devs want you to craft. If murdering every bunny you see gives no XP then the devs don't want you to go on mass killing sprees of the NPC fauna. Sometimes they'll even include it as a joke and give 1 xp. Feel free to kill 800,000 bunnies to level up (disincentive without banning).

Like all things in the book, it's one idea DMs are free to take or leave. Variant suggestions exist because the idea is not definitive or mandatory for the game experience. You are free to take as much or as little of the book as you want, establishing the rules as guidelines rather than a war game's hard-and-fast strict structure of permissions. It's a mechanic that facilitates what it aims to do -- assist the storyteller.
I see no reason to replace XP with anything. It's useless and serves almost no point within a table top RPG.

For the DM, variants of XP can be a pacing tool, though the games I am thinking of where XP drives playstyle (good looted = xp), also dole out xp too slow for my players to retain interest.