The difference between a field guide and a cv is that with a field guide you are naturally forced to compare features as you look through the options, the cv gives you top recommendation and by including a button you can click to ad an id it makes it extremely easy to not look at other options.
A better comparison that I actually see on the platform would be a tour guide/park ranger(or even a sign in a park) tells you what something is vs the CV, often the tour guides get it wrong (wrong species/outdated name/ misremembering the spelling and etc) which is totally normal as we’re all human and people trust the tour guide and make an observation without comparing other options. I have seen many cases of this while identifying on inat since people often mention in notes or in comments after their id is corrected, and there are probably way more that are missid’d that I cannot attribute bc I don’t have that information.