It is a Mitzvah if the purpose is to reenergize.
I don’t know – I don’t see it as so hard. To me it’s a basic concept of Yiddishkeit and one that I was aware of before seminary.
And the fact that you need to reenergize doesn’t meant that your Avodas Hashem is not important – people are complex and have emotions and bodies that need taken of in order to function and be ovdei Hashem. That is how Hashem made us.
I suspect that boys may be different than girls in terms of how they relate to these things. I think this may have to do with girls being more “spiritual” and into hashkafa and boys being more black-and-white and into halacha. I think for a boy it may be harder to relate to a non-Mitzvah activity as part of his Avodas Hashem. This may be related to the fact that for a boy, his Avodas Hashem is mainly about learning Torah and it can be problematic for him to ever do anything but learn (unless he has a very good justification). For a girl, her purpose is more about doing everything l’sheim Shamayim (as opposed to learning Torah and performing clear-cut Mitzvos).
Or maybe, everyone is different, and different people have a harder/easier time with different things.
But I think I know many people who live this way (at least on a basic level), including children. And I don’t think it’s a problem to give it over to seminary girls. And I do think it’s something that many (if not most or all) people are capable of. I could be wrong, but I think that people who think it’s beyond them are either underestimating themselves or don’t understand what the concept means.