As a driver, I'd be totally up for splitting the gas money with someone, but as a passenger it just seems like a more expensive offering with no increase in benefits for me.
Are European buses or trains more expensive?
Drivers have to coordinate pick up and drop off of passengers, which is a pain, especially in LA. On the other hand, passengers getting dropped off can also be a huge benefit since the bus stop probably isn't your final destination.
In general, Europe is denser (more cities within a closer distance), gas prices are higher, and people are maybe more trusting of strangers.