Levels could mean something
So, we have this concept of levels in duolingo, for now only as a motivational factor. But it could be more.
For example: A level 10 ( or so) could be required in order to be able to do immersion. And A level 20 could give you a status as moderator in immersion, being able to finalize translations (end discussions) and in general.
These are just two examples, there could be more, where a higher level could give you access to different parts of duolingo, and thus increase the motivational aspect, and duolingo could benefit from the skills of those with more experience and knowledge.
The problem with this is that levels aren't tied to anything but points. Levels don't necessarily indicate a person's progress on Duolingo, much less their actual skill level in a language. I'm level 17 in French, the same as you, but only around a quarter of the way through the tree and still not very knowledgeable about that language.