Hi, not a stupid question at all and yes, unfortunately this is temporarily disabled. I wanted to release this update, but the music import thing was still pretty broken. I'm on iOS 10.2 beta and the music picker (the thing Apple provides to let you choose songs) doesn't really work at all. I'll have to wait until 10.2 gets released to fix this the way things look. So I decided to take music import out temporarily.
Again, sorry but this feature will of course come back soon!
edit: and yes, next version will always let you choose a segment for importing if the source sound is longer than the sample buffer.