Actually, almost all levels on odd strata give less than 560 crowns, and really only act as a speed bump on the way to the clockwork terminal and even strata. But Treasure Vaults do give significantly less cash than other levels at the same depth.

I'm not impressed with the minerals or consumables in Treasure Vaults, either. There are many mineral columns, but they seem to be significantly worse average quality than in other levels, so that the final take seems to be about the same as most others (besides, even a huge mineral only sells for about 18 crowns). And Vaults give far, far fewer consumables than most levels; you may not use any, but your accumulation is still worse than conservative play on most levels, plus you risk losing some if the Kleptolisks get lucky (they seem to drop whatever item they steal, but they steal an entire stack and only drop one).

Sparks are definitely worth considering, but I doubt I could convert them into crowns at better than 150cr/spark, and I wouldn't be surprised to get less. I'm not sure exactly what the average spark drops are on either Treasure Vaults or normal levels, but I'd estimate a difference of about 1-1.5. That might bring them up to par with normal levels, but definitely leaves them less lucrative than the Graveyards that always appear at the same depth, so they're never what I'm hoping to get when I step onto a random elevator.

If Treasure Vaults are supposed to balance out Graveyards, I suppose they may be doing their job--though perhaps not in the way that the designers intended.

They're definitely far closer to the average than Arenas, though--and if Arenas are supposedly justified on the basis of difficulty, then Treasure Vaults are similarly justified on lack of difficulty. Rebalancing Arenas strikes me as a far larger issue, though the rewards on all levels probably ought to be adjusted as part of a single initiative.