All three of my bodies (X-E2, X-T4, GFX100S II) have shoot without lenses enabled and they have all had it set since I bought them.
No harm in it at all. Just remember to set the focal length when you fit a manual lens with no electronics otherwise the IBIS (if you have it) goes nuts. I regularly use vintage film lenses from Minolta, Zeiss, Mamiya, Rollei and others on my X mounts along with more modern manual focus stuff from TTArtisans. I also use Nikon AF-S lenses with a Fringer so the world is your oyster!
Vintage lenses can be an absolute bargain too - For example the Zeiss 135 f/35 in M42 is as cheap as chips and very sharp as is the excellent Minolta 35-70 Macro (which is also rebadged Leica).