Notwithstanding, Campy has been testing its electronic components for the past decades or so, and I'm pretty sure Campy wouldn't release the EPS unless it's reliable.
I've not heard much ( if anything at all) about the EPS V2, but two of local bike shops that deal with lots of high-end builds have steadfastly declined builds of the EPS V1 after running into a fair number of issues on the earliest batches.
And also, the way the wire harness was done, if you have a dead battery or faulty circuit board, its plenty of hassle ripping out the entire hardness just to replace the battery/brain of the system for V1. Not something any bikeshop would like to deal with. Not being able to replace the battery on the fly was another cited concern.
I don't know why there was a need for a magnetic switch as a whole for the EPS.
Even from the initial Di2 7970, the system could be left with the battery connected for months without issue. I once left mine on the shelf for 2.5 months while I was away on job assignment. Came back, batteries were still perfectly functional for a 5 hour outing as I completely forgot about checking for charge in my excitement to get out for a ride.