Yes and no. It is a great pacifier, but my grandma of nearly 90 years old also legitimately understands any english that comes her way much better after doing that on duolingo for a few months. She enjoys it greatly, I do not understand how with all the advertisements and ten types of currencies/points/lives that I cannot make heads or tails of but she likes it.

Especially the animations, she often remarks how cute they are and wants to show us. It's adorable and I'm super happy for her :) though also disappointed that, when I installed duolingo for her, it wasn't the innocent learning app with good UX that I knew it as from like six years earlier

It being a pacifier and it enabling some (read: non-zero) understanding of a language are not mutually exclusive. You exemplified my thesis.

Your "thesis" rather sounded like it was exclusive since you said you didn't learn one "lick" after maxing out the available content for two languages, but I'm glad we apparently agree after all