It depends upon what you're trying to accomplish, and for whom. Are you trying to make money from casual language dabblers? Create a useful resource for people whose livelihoods depend upon learning a language? Teach yourself?

I tried learning a language via Duolingo for a while. I treated it as "free flash cards with pronunciation," and tried to ignore the gamification and cutesy animated characters. I ditched it when it went all-in on AI slop. I've since found a free 1990s-style website that has common phrases, conjugation rules, etc. with pronunciation, and have learned much more.