Many places don't handle those files properly. For selling on eBay/Mercari/Poshmark, if I AirDrop from my iPhone to upload from my computer, they don't convert the file properly. (Typing descriptions etc is far easier from the computer than on a mobile app) I can setup an Apple Script to do conversions, but I've found uploading to Dropbox and pulling from the desktop version works better (Dropbox does the HEIC-JPG conversion)

I believe the onus should be on the trillion dollar company that chose to use a non-standard file format.