VZN has a nice concise set of bands on it, but ATT is the same as generic, and there is no TMO profile.
Having VZN cut down to it’s six main bands really helps when mobile - on ATT/TMO it can get confusing. Either I have to remember what carriers have which bands, or look it up and manually uncheck all the ones that they don’t support. I do the latter, but with all the unchecked boxes I can sometimes forget to recheck a band5 or something before moving elsewhere.
The list would be updated with firmware updates, which should keep things in parity with the real world (and if not, one can just select Generic).
This ties into (most) of the concerns in other threads like Custom cellular band selection note column but doesn’t require any new engineering as the functionality exists, just more config to keep track of.