Haha! If you don't use the site particularly often, that could be a factor - I can't cite it, but I am sure I read that one of the factors they take into consideration is a potential contributor's activity on the site, to alleviate the risk that people start contributing and then disappear soon after (which does happen from time to time). They also usually invite only a couple of contributors in the very early stages of development, and then a few more as the course progresses, so you never know - you might get an email down the line
I've reached the last three lessons of my Duolingo tree for German, and I have to say I have found it to be a very valuable tool. I personally would never recommend it as the one and only means of learning (some users seem to treat it that way, and I feel they're just hamstringing themselves); I use many other resources in addition to it. Duolingo tries to take the focus away from explicit grammar explanations, but I personally feel much more comfortable knowing grammar. When I use it as a means of quickfire exercises to apply what I've learnt elsewhere, or to get to grips with the basics of a new concept.
It's mostly devoid of nuance, but I feel like it's given me an excellent basis to progress from. I can read simpler books fairly well (I struggle with longer, more complex sentences at times). I have some way to go to be able to understand movies/radio etc. - but that's more an issue of slow processing which I need to speed up, as if I pause line by line I can get there. I can have spoken conversation with Germans, but it's certainly full of the simplifications Luis mentions in that article. I've been learning for five or six months now, and have no notable language experience prior to that: compulsory french lessons in school which all but killed my interest in languages due to the teaching; I'm much more advanced (only speaking relatively :P) in German now than I was after four years of French, though I had no particular enthusiasm or drive for it in school. Based on my experience with it, I definitely think it's possibly to achieve that if the Irish course is developed to a similar quality.
I should also note that when a tree is first released, it is often full of issues which have to be corrected via user reports (there are still some in the German tree). Most common is a translation which hasn't been submitted as a potential correct answer, as the course developers can rarely consider all the various ways a speaker might phrase the answer (Duolingo staff have said some sentences can come to around 500 correct potential answers). The beta release will depend on users who know the language reporting errors in translations, as well as reporting alternative solutions. A language tree graduates from beta when it receives under a certain number of reports per lesson for every lesson, if I recall correctly.