There is an excellent motivic analysis of this piece by David Bennett Thomas.
For the question about beaming: This piece is built, like a Bach Invention, from the development of a single melodic motif. The beaming is used to make that motif clear, even when it gets rhythmically misaligned relative to the barlines, or split up by rests.
The bass clef is more puzzling. It doesn't seem necessary, and it may well be a typo, as others suggested. I note that it is not present in the analysis score that I linked above. However, its worth pointing out that this is the first time in the piece that the left hand goes that low in the bass, so it might be a friendly reminder that we aren't switching back to the treble clef again, and that the piece really does go that low. It's hard to say.