Why is spending lingots and inviting friends to follow you language learning achievements?
Why does Duolingo list these as achievements?
It's not really related to the language learning aspect of Duolingo itself. They're just fun little buttons that people like to "collect" for their profile, I suppose. Don't sweat it if you haven't earned them, they're only a random feature that adds to the "gamification" feature of Duolingo.
I have only spent 175 lingots, according to Duolingo. I give them away all the time and would gladly spend more, but I have bonus skills in multiple courses, both Duo suits, a streak freeze, timed practice, double or nothing (always).
How did you manage to spend 200? I need some tips! (please and thank you ;-)
According to Duolingo I've spent 110... I'm only missing the owl suits, which amount to 50 lingots... so the maximum I can reach is 160...
Have they forgot how poor the store is when they came up with that 200 lingots threshold?
1) I think on the Android App version of Duolingo, there is a weekend amulet costing 20 lingots that can appear on Fridays in the store.
see discusssion "Weekend amulet is expensive compared to a streak protector"
2) You could also try to invoke a progress test (which costs lingots). User Woof explains the procedure he used in the discussion thread, "Is there a way to test your progress to see how well you are doing?"
They're not proper learning achievements but rather small stuff to spice up the whole experience. Still better than dressing the owl... though I have nothing against those who dig it.
Achievements are meant to motivating people, you generally also want to have easy achievements to be able to motivate even those who haven't gotten far yet. Additionally inviting friends attracts new people to Duolingo and learning a language together with a friend can motivate you or even give you a conversation partner. The spending of ingots makes people check out the things they can buy with them.
In conclusion: I can't really think of any disadvantages while they can be beneficial for some. -> thus overall I'd say it's not really something worth complaining about.