It found rush hour without being told

Look at the first column of the hour factor matrix. The strongest pattern peaks at hour 18 — and that is also the busiest hour in the raw counts.

The decomposition found evening rush hour without being told what an hour is. That is expected rather than magic: every entry is a trip count, so the strongest pattern along the hour axis follows how busy each hour is. It found the dominant pattern along that axis, because that is what a decomposition does.

This is the result worth carrying out of the section. The 4.7× compression is the cost saving; this is the reason to decompose at all.