Yes, an ITU-R BS.1770 meter can be useful during mixing if you for example have several vocals takes that need a certain alignment. Definitely no doubt about that.
But I see the ITU-R BS.1770 specs as definite future in terms of mastering as it combines several meters into one (and this is the reason why i created the concept in the first place), while I still use the “old ways” (digital PPM, VU) during mixing.
To each their own indeed. 