Macbooks aren't the absolute best example anymore, since 20W is plenty to charge ARM-based MacBooks in a few hours, so a 200W 10-port charger could do a fine job with 10 MacBooks.

But your point is still valid. As a nerd I really appreciate being able to use say, my 100W laptop charger or the car jumpstarter pack I have to charge up my earbuds or an electric toothbrush, since it reduces the number of weird little cables or chargers I have to keep track of, but it sure does baffle the non-technical majority that their toothbrush charger fits their laptop 'for some reason' but of course does nothing - plus the confusion when they realize they could physically plug the toothbrush into a pair of headphones, or plug two portable batteries together.