Given a choice, I wouldn't do any miles on the turbo at all. They'd all be done outside on nice, smooth, traffic free roads at a pleasant 18 degrees, gentle breezes at my back and noon sushine up above...
As it is, the trainer will have to do some of the time so I count them, not to earn chufty badges off strangers or impress my mates - it's merely as a comparison tool, month to month, for me. If time wasn't at a premium then maybe I'd be less bothered with logging all this info, but being time poor (like most people) it's handy to compare & assess exactly where you're at bike-fitness wise to a relevant period in the past based on time / mileage put in. The 'miles' done on zwift are always done faster IME due to not having to steer, balance, avoid other road users, sit at junctions, apply the brakes, do a stint into a headwind, not having a 6 man draft etc etc etc but they're concentrated miles. I can maintain 22mph on the flat just the same on the road as I can on zwift given the right conditions but how often does this happen IRL? Personally I find riding an hour on zwift to be far harder physically than riding an hour on the the road so I feel no shame admitting it, but it's not compulsary to count them so do whatever
you feel comfortable with, other people's opinions are just opinions.