Well as far as being good enough to pass your checkrides, you should be able to do a good enough slow flight per the PTS anyway, but in regards to experience flying cross countries it would seem like the basic experience, and the major errors is gained through the normal cross countries of the private, instrument and commercial, and the extended experience is more gained through doing it again and again.
So from my point of view, I don't really see the point, and your comparison is a bit off imo