Pvt. Winslow
Explorer
This seems like kind of a self-correcting problem.
Say player A blows through all of their spell points in battle #1. Then the next 3-5 battles all he can do it use his cantrips. He'll do very little damage and have no variety on his actions. That's not much fun for him, so the next day he tries to space out his point usage. That's what I'd do anyway.
I think your characters would quickly learn that blowing all of their points in one battle is kind of fun for that one encounter, but the rest of the day quickly becomes a drag.
Generally when someone references the 5 minute work day, it's assuming that the caster who exhausts all their resources early on is able to convince the rest of the party that they need to rest so he can recover. There's been a lot of arguments over the 5MWD in the past, some sides saying you would have to be the world's biggest idiot not to rest and let the Wizard recover because you are literally putting your life on the line, other sides saying that as adventurers you'll often have time constraints and people you need to save who won't survive if you just take a day off.
keterys is right though, in that spell points actually make it even easier to go nova (aka use all your most powerful spells in a really short period of time) and make a huge impact on your encounters in doing so. Still, I don't think spell points make the 5MWD all that much worse conceptually. People who would do it, will still do it, with or without spell points. Those who budget their spells will do so, with or without a different spellcasting system.
When it comes to spell points, I worry more about the impact of extra higher level slots than I do about casters going nova in a short period of time.