It does not matter. Some people mythic raid and some people work on character progression which includes things like earning essences and leveling up professions.
The only reason I got exalted in Nazjatar and Mechagon on 6 plus characters plus did all those follower quests was straight for essences. I would not have done that content on my alts otherwise.
If what that person was saying was accurate that people would still be doing the content, there literally would be NO need for account wide essences.