You are absolutely right. Especially if we are talking about BSD or Unix proper. But, there is a cognitive load to remembering what machine you are on, or if certain variables have been set and so on.

I have been on machines that fire up nano with crontab -e, in the name of user friendliness. These same machines will not respect EDITOR or VISUAL anyway, so I have no idea what to do about them. I usually just get up and creep away making sure not to turn my back on them.