The concept has just one niche I can see (besides people who are scared of flying)... getting into downtown SF before 8am without the chance of your flight being delayed due to fog. If you absolutely need to be at a meeting at 8am, currently you’re flying in the night before, grabbing an Uber from SFO to a hotel generally close to your morning meeting, hoping you’ll get a good night sleep and then dealing with the mo…
On reflection the other issue is that it doesn't go direct into downtown. But you can transfer to BART at Richmond so same same.