[Tagging] surface=pebbles -> surface=pebblestone ?

[Mateusz Konieczny]

surface=pebblestone is documented at
http://wiki.openstreetmap.org/wiki/Key:surface and used 23 537 times.

surface=pebbles is not documented and used 555 times.

Both seem to have the same meaning.

Is there any good reason to avoid changing existing surface=pebbles to
surface=pebblestone?