A couple of questions!
First is about your reasons for doing this. Is it because you wanted to introduce a money sink into your campaign's economy, presumably so players won't want to spend all of their money on magic items? That's the impression I'm getting.
Second, what would you do if one of your players had a non-materialistic character? Not just a vow of poverty (because charitable donations would easily fall under your XP guideline), but more of a self-sufficient loner who neither needed nor wanted to worry about cash? That character would have a very hard time earning XP in your game if he remained true to his concept.
Back in my BECMI/AD&D days, I always thought the concept of XP for gold was a strange one. I'm sure it can be made to work, but I have a feeling you're going to run into a lot of trouble at higher levels. You're basically asking your PCs to fritter away 10,000 gp per level on nothing. Unless your economy is extremely inflated, even the most dissipated playboy might find that overly frivolous.
But what else is there to spend your gold on?
Assuming a 3E-style campaign where you run published modules with characters focused on meeting their goals (as set out by the adventure: freeing the princess, killing the baddie, breaking the evil artifact and so on) for players not interested in "a greater picture" for their characters (building a castle, setting up a guild, managing a laboratory etc).
The players will still want to spend all their money on magic items, since all they care for is using their characters as vehicles toward adventure success: more powerful characters equal a greater chance of reaching goals without PC deaths. I imagine this playing style to be one of the most common in the d20 era.
Now, to your questions:
I want to try "xp for gold" because I am aware that
1) there is nothing to spend your gold on in 5E (in the short term)
2) magic items are much less required in 5E
3) I like the idea to encourage players to find solutions that doesn't always involve head-on combat
This makes me conclude another money sink is needed; one that still allows the occasional purchase of a magic item. Essentially, you buy magic items with your xp - buy too many, and you fall back in level relative to those of your companions that settle for looted items only, buy too few, and you lose opportunities to become more versatile, if not outright more powerful.
I could run a "default" 5E game where money is used to enrich your PC's background (history, allies, place in the world), but I know my players aren't very interested in stuff that doesn't tie directly to adventuring.
I could skip placing gold in monsters' pockets, making the problem of spending it go away entirely, but that feels very strange for a D&D game.
And so I thought that a marriage between "xp for gold" and carousing tables would fit the bill. It would mean that PCs do have a life outside the dungeon, but it would be structured and not something to spend much play time on.
I am still very much surprised that
a) WotC have created a game that does not seem to support the playing style I associate so strongly with d20-era D&D
b) so few of you share my complaints. I would have thought lots of players played the game "kick in the door, loot the corpses, upgrade"-style, but perhaps they don't frequent EN World...
Zapp
PS. Regarding your "non-materialistic loner" character I must say I view that as a very special corner case. It certainly won't be any of my players making such a character! ;-)
But still, I don't see the problem. Assuming a player insisted he could make the concept work, I would have no problem making his share "disappear" and granting him the occasional "gift" from his friends or backers (or just lucky breaks, if he's truly a loner). In essence, managing his economy invisibly. But it most definitely won't be a problem with the players I've got...
Regarding "fritter away 10000 gp on nothing": how well are you acquainted with the rich and the fabulous (in our world). I'm sure you can see how 10000 gp is nothing for a character traveling the planes, besting demons in single combat, and deciding the fate_ of nations on her whims...
Heck, you don't even need to go high-level zany bonkers for 10000 gp to be next to nothing. Even at mid levels, where characters visit large cities and interact with regional movers and shakers, 10000 gp is nothing to sneeze at, but it would not overwhelm these NPC players. Roleplaying games are traditionally made by geeks completely clueless about economics, that grossly underestimate how much capital circulate even in a modest economy, say a guild, a church, or a small city.
Heck, if you gave
me a million dollars it would still not be enough to transform my life. Sure, it would be nice (very nice, in fact) and it would ease my life in several ways. But it would not be enough to retire on. It would not enable me to buy a haunted mansion and cacklingly play the organ all night

It would not be enough for me to out-do Elon Musk and invent interstellar travel. And so on...