It also contains opening hours, addresses, etc., which is all in OSM. I don't understand why people always try to start anew when the data is right there. I can understand there is some complexity in getting your user's contributed data back into OSM and dealing with edit conflicts and abuse, but at least use it as a starting point and see about contributing back later.
(Also, Google Maps is such a confusing map, I hardly even recognize the town I've lived in for 20 years. But that is probably because I'm used to OSM.)