I never discourage it, as it really does work for some people and is very accessible, but I DO encourage using it along side other resources like Tofugu, Bunpo, or Bunpro to better understand how the grammar works!

Duolingo is alright to get familiar with the language, some common phrases and sometimes when you just can’t start a textbook. Renshuu is obviously better if you are serious and you want to advance much faster and have everything all in one place. Other apps like Bunpo, Lingodeer etc work much better if you are paying so it’s up to one to decide what is best for their study method.