Exactly!

As I said, I have some that are those enormous bricks, about the size of 2.5 iPhones stacked on top of each other; it’s a nightmare to use. No big deal if you can sit your phone on a table or in your car’s center console while it’s charging, but it’s a gigantic pain to lug around.

The 621 is small enough that I can always keep it with me without a thought, and slap it on the back when I get around ~60-70%, and I can still actually USE the phone…

I really like mine!