What are your metrics for “effective?” As someone who is both teaching and taking classes currently, I can tell you engagement is pitifully low in online formats. Education is not just about memorizing facts and going through the motions to get a good grade. There’d have to be some amazing innovation in online education practices to convince me it will be the default anytime soon.
I remember easily getting gems for free. Also the streak basically doesn’t matter at all. What made me uninstall is the slow pace. It felt like I was stuck on the same words and topics forever. It felt like I was not actually learning anything, which if you’ve ever started learning a language if a formal setting, is very apparent.