Removing Reserve XP won't materially affect the economics in the long-term, as spending on Reserve XP tends to drop dramatically at 7th level, when Restore Life and Limb becomes available.
That makes sense, thank you.
That said, I'd encourage you to leave the system in, because it is a very valuable role-playing stimulus.
This may just be a difference in groups, then. Several of my players were spending money uselessly before
they knew about the reserve XP system; and the others seemed to be getting in the spirit.
I mean, this is a group that spent money and game time taking a war dog to a local salon for shampoo and pampering.
What I saw happening, however, was that after we discussed reserve XP … the players started asking accounting questions about their previously freeform spending. Galswintha refused to spend less than 6 gp/week on her iron rations, and now she wants to know if the extra 5 gp/wk counts towards reserve. Lotharic wants to change the amount he was voluntarily tithing to the “optimal” amount for his current level. Chlodomer, after adding up the drinks he keeps buying for strangers, asks if the goblin-sized beret he bought for Grizzba counts.
So … for this group, at least, it wasn’t needed to stimulate role-playing spending, and it actually seems to be turning what was just “fun spending” into an accounting and meta-game tool.
If I was running a game with a bunch of strangers, or a group of serious hack-n-slash optimizers, I would probably leave it in, both to encourage role-playing and as a fun meta-game.
But for my group … meh. I’d rather see the girls turn their ferocious war dog into a lap mastiff. (When they pinky-swore vengeance on the ogre? It wasn’t because Radegund died and probably filled the belly of an ogre - no, it was their precious, shampooed puppy that got them all riled up.)