I don't understand all these comments saying that Duolingo is useless? Maybe your brain is not very fit for acquiring a new language, but the app is nothing mor

I don't understand all these comments saying that Duolingo is useless? Maybe your brain is not very fit for acquiring a new language, but the app is nothing more than an easy way to do small exercises. That can be pretty useful by itself, if you really have the motivation to do it a lot.