Yes, powerwashing would be wanted. That's an IP69K, not too hard to hit with some basic mechanical protections.
Unless you need delicate sensors which need direct contact to samples to work.
Maybe it's not a complete necessity, but generally it's gonna be mixed in with big farm equipment that is power washed. The more you have to "coddle" the equipment the less cost effective it'll be for farmers.
Farm workers generally know how to wash themselves. Still I'd wage good money farm hands have used power washers on each other. Probably work well to clean off work coveralls!
Strictly it needn't be if it offers an even better solution, but, realistically, what startup trying to introduce a new technology (that isn't cleaning technology) has time to also develop a novel way to clean things? It is such an unlikely scenario that it isn't worth considering.
Is that a necessary requirement? I mean, that would probably damage current harvesters, who are human people.
I mean, there are lots of parts of cars where pressure washing would probably force fluid into the bearings.
Might that not apply to hydraulic, pneumatic or electronic systems too?
(I do get what you're saying though)