But I’m sorry, safe infrastructure is more important than how fast you can ride down Valencia. As to the question of whether physically separated bike lanes are safer, then answer is unequivocally “yes”: https://www.treehugger.com/bikes/new-american-study-confirms-physically-separated-bike-lanes-are-crucial-safety.html

You may be confusing the things SFMTA calls “protected” with actual physically separated lanes. Raised lanes are not physically separated. Lanes guarded by soft hit posts are not physically separated. For examples of actual physically separated bike lanes, look at (parts of) the recent projects on:
13th, 7th, and 8th: https://www.sfmta.com/about-sfmta/blog/happy-bike-work-day-new-protected-bike-lanes-and-bike-count-webpage