It literally is maybe not by your metric but someone elses metric that can absolutely be a success. Sometimes getting up in the morning is a success for people I've been there I know what that's like. I'm kind of amused at the gatekeeping of what a 'success' is here. Guy said he has literally learned things that have stuck with him sounds like something he marks as a success to me, not like he was taking the course for college credit and had to demonstrate fluency lol
edit: yea the guy is now consuming media in a foreign language and has had small convos based on what he learned on duolingo. idk man smells like success