We have thought about using a manual switch like that before. The reason we haven't so far is that the ARB compressor wiring and fuses have been the problems for Stephen so far in Wally not the actual switch itself.
In TTC he blew a fuse in the Tank trap that caused us to loose the ARB compressor.
It seems that as long as the compressor will run the rest of the system works.
Our experiance and knowledge of the subject. I put the electric switch in my buggy and it works so far even being very wet several times
My .02