I had two wheel sets - offroad one with 27.5 x 2.2" and road one with 700 x 32c.
Would swap to the road one when I wanted to get some base miles and do some road riding but eventually ended up selling it as I've got a major fear of being run over by a motorist and I don't ride road too much.
Have anyone actually done this? The only one I know is a customers with a MOOTS having 700 x 32 and 700x 40