The second shortcut seems to be to sleep goal + bedtime reminder. In my opinion this does not make sense. I always use this option to compensate for the smart wakeup period. So it would make more sense to have it as sleep goal + smart period/2. This way you hit the sleep goal on average because sometimes you wake up a bit before it and sometimes a bit after.
Having it based on the bedtime reminder would only make sense if people were starting sleep tracking when they get the reminder which I don’t think is the intended usecase.