Yes. Currently mappers tend to scroll the mouse wheel while playing the map to make a quick overlook at a map (both in modding and editing). This works but it has some disadvantages.
First, it cannot check sound samples. Using 200% replay in playing mode can do this but it can't stop real time, and time switching from play to edit takes large amount of time (since you have to switch many times).
Second, its images of flow and blanket is fragmented. Experienced mappers can scroll mouse wheel once to check flow in about 4 beats, but this technique is quite meaningless, and can miss a lot of notes.
In contrast, quicker playback can help mapper give the smooth look of a map in a short time. When they check issues I listed above they don't have to use 1x playback and take a lot of time, or scroll mouse wheels to manually accelerate it.
Furthermore, if the mapper has already get a clear ideas on the beats of the song, they can use quicker playback in mapping new difficulties of the same song they have mapped. This especially works in Easy or Normal difficulties, when mapper only need to follow lyrics or the snare.
That's why I think it is quite useful to enable quicker playback.