What you said is quite correct.
But, the basis of the discussion is pointless.
If you were looking at the frequency response of a moving iron meter, or the electro-dyno thingy discussed in another thread where the field coil is excited by the supply, as is the moving coil, then yes there is merit in what you say.
But to try and compare a moving coil meter with a digital display meter is like trying to compare a car (automobile) with a boat, which one is best?
A car is faster than a boat, but if you want to go across the water, what good is a car?
Just because a meter is digital, does not mean it will work better at high frequencies that the moving coil meter.
JimB