Looking at a map of this eBART line (physically a separate 10-mile line from BART but from their own system map's point of view just an extension), there are only three stations -- the Pittsburg/Bay Point transfer station (a short ride from the existing Pittsburg/Bay Point BART station), Downtown Pittsburg (AKA Railroad Avenue), and Antioch (AKA Hillcrest Avenue). So the line only has two endpoints with one station between it, or an average of 5 minutes ride between stations. That's a long time, and it reminds me of the long run at the temporary end of Washington DC Metro's Silver Line between Tysons Corner and Wiehle Avenue/Reston.
However, it looks like BART missed the boat in picking station locations for eBART, as the line will bypass what looks to be a very commercial area with several shopping centers, a large shopping mall, hotels, and many major restaurant chains. It's at the interchange where CA 4 meets Auto Center Drive and Somersville Road. The Somersville Mall is a block away from where such a station would be. They should consider that location for an in-fill station now that eBART will open without it. Plans meanwhile continue to bring eBART further east to Brentwood, but let's see how the maiden route runs first and interfaces with regular BART when everything is open later this month.