I would not be pessimistic about Trump’s chances in California. Lots of Republicans will take advantage of the ballot drop boxes and many votes will be cast for Trump.
My formally super liberal niece in West Hollywood bought a gun up where I live and says that she’s having conversations with the people in her neighborhood and a lot of people are voting for Trump. I know this is anecdotal but with all the other evidence I see that people are changing their minds tells me that all is what it doesn’t seem in the media.
Even if President Trump loses, their vote would help whatever down-ticket Republicans remain.
A secondary benefit is that it would raise the popular vote count, diluting the phony "But Biden won the popular vote!" argument.