I'd divide your question into two parts:
1) Do I need Pool Perfect? No, you don't. As far as I can tell, it will do nothing for you.
2) Do I need Phosfree, phosphate remover? If you test your water and conclude, on the basis of those tests, that reduction of phosphates is in order, perhaps. "A properly sanitized pool" implies a pool that never drops below the minimum required free chlorine. Apparently, from the amount of "algae complaints" we hear, there are a lot of pools that drop below that minimum number and Mother Nature's punishment ensues. Algae feeds on phosphates and starving them can't hurt, if you are prone to letting your FC drop below the minimum.
So, I conclude that if you have a regime of testing for FC and never let the chlorine drop, you probably don't ever need to worry about phosphates. If that isn't the case, you may want to read further and develop an iron clad regime of testing and response before buying "stuff" from the pool store.
FWIW, I use borates and check for phosphates. Maybe not necessary, but with proper testing and judicious use, they are cheap insurance against that unanticipated algae bloom.....