I think the fact that you dig up a huge chest every time let's people expect too much loot. Therefore I'd change it to something more mundane like a crate for average loot, that way you get exicted when you dig up an actual chest and not disapointed when it's just a crate which contains minor loot.
That doesn't really address the core of the problem. It's still something that you are digging out and opening only to find some pittance in it.
It makes you question who bothered burying it, why did you bothered digging it out and more than anything why the devs/designers thought this kind of busywork for pocket change would feel rewarding.
Nah, I don't need "crates rather than chests". Make most of them go away and the remaining ones harder to find and more valuable.