Duolingo is free and convenient. That alone makes it better than a lot of tools. With a few months long streak in Italian, I could get by on vacation & get the gist of some sports blogs. I think it's fine if people aren't motivated to go beyond this point.

It really did help with vocab. No, duolingo didn't teach the finer points of grammar, but it's not like native speakers speak like Dante wrote anyway... These experiences have also motivated me to explore other ways of learning Italian. That wouldn't have happened without a free and convenient tool like duolingo.