Great, I have able to test on my VPS that work fine, but running pagespeed:
Mobile
70 (without PhastPress) vs 43 (with PhastPress)
Desktop
94 (without PhastPress) vs 95 (with PhastPress)
Those implemented web server rule to block PHP files in wp-content and wp-includes will make PhastpPress non-functioning. It seems there are lots of challenge and efforts to add optimizations compare to other CMS that could be optimize right from the very beginning.