The more the turns the lower the Kv and rpm. 15 turns only on such a small stator means a very high Kv and rpm. There is a trade of course, the more the turns the thinner the wire.
The controllers are not too happy if the emf voltage is low, and lrk winding is a risk factor too.
I am not absolutely sure, but think so that this winding
is similar to the lrk in the (mechanical rpm)/(electrical rpm) value. There are several manufacturers of so called lrk, but most if not all of them producing motors with windings on all of the teeth. They do it for better efficiency and less controller misfires.