I have seen these coaches all over San Jose the past few weeks and along I-5 this week to/fro Anaheim. Looks like relatively new service routes and good alternative to MegaBus and the Chinatown buses.
The Los Angeles (Union Station) to San Diego (Seaport Village) line looks like a viable option for those contemplating a full but feasible daytrip. $8 each way and they have 7am LA departure and 8pm return.
The Bay Area to SoCal route will definitely be popular.
Complete disclaimer that I have no financial ties to Bolt. Decided to research after seeing the buses and a recent thread about Greyhound.