Whenever I see a experimental mage I fight them, because of their random affixes having a chance to high roll into something amazing(have not gained their glyph or rune yet though)
But mono caches do not drop anything special, being not much better than the chest at a mono end, if they gave a random mono completion reward then they would be competitive with shrines and their occasional idol drops - but getting a bunch of normal loot is not exactly enough to distinguish them from just killing a bunch more enemies.
So having learned a lot about caches as I ahem… Target farmed them to get some runes of ascendance…
The higher rarity ones drop quite a bit of exalted of specialized type and the highest tier always drop a unique relative to the type of box, they can drop more then 1 as well.
so you can in theory target farm caches to narrow down loot by running through monos fast looking for weapon boxes to spit out tons of exalted weapons.
sadly outside of doing it the… efficient way, I dont think you will ever see enough boxes fast enough to print rewards.
I actually think the higher rarity boxes are quite rewarding. the highest tier weapon box drops 5-6 exalted weapons narrowed down by type. if you could target farm them reliably it would be a simple way to get lots of weapon drops if thats what you are after etc.
I think maybe the play is actually not to buff the caches, but let more then 1 spawn in an area.
The devs have said corruption does buff the appearance rate of the boxes as well as their chance to be higher tier.
I also think the only interesting one is the one that gives you runes and the key box. The gear boxes should just be removed because again they promote running to a thing, clicking it, and not killing monsters.