Back-in-the-day when electricians wired most existing construction, MWBC's were in the same-predictable locations.I had one multiwire branch citcuit and wasnt spending the money for that one...
Occupants with GFCI outlets at these kitchen or laundry points of use, fed by MWBC's, rarely complain about the $30 AF/GF Dual Function outlet that typically works fine, after ~100 replaced per 406.4(D)4.
Unlike the members on this forum, my clients get how utility issues can trip AFCI's, and how to unplug stuff to check it.
Internet opinion is much harder to convince what my clients experience in the field on a daily basis.
However, since I'm not a paid evangelist of AFCI's or empirical observation, I am learning to leave the internet alone.