I assume SWA is trying to be pro-active, in response to the constant complaint (regarding all airlines) that passengers aren't given enough info about possible delays. Many passengers seem to value being kept in the loop and updated as the situation changes.

You should still get to the airport in time for your original departure. With the frequent morning fog and ATC delays at SFO, the ATC ground holds are a moving target. A ten-minute hold can turn into a 2 hour hold in the blink of an eye... and vice versa!