polish before applying sealant?

Intending on claying/nanoskin my 2012 Camry, then applying Blackfire Wet Diamond All Finish Paint Protection. I suppose this is a sealant. I read that applying a polish is required prior to applying the BD product. What is the purpose of a polish even after the car has been clayed? tks

 

Polish is not required before applying a sealant, however it is recommended. Claying removes above surface paint contamination, paint over spray and industrial fallout. Paint contamination is tiny metal shavings from rail dust, brake dust, and industrial fallout. Paint contamination can be felt as a "rough or gritty" texture on the paint's surface as opposed to the “smooth as glass” texture. After this process the paint is left clean and smooth and ready for either compounding or polishing.

Polishing will remove light defects and light swirls and bring the paint to a high luster and gloss prior to applying a sealant. Paint Sealants, composed mainly of polymers, designed for long-term paint protection and easy application. Paint sealants last longer than carnauba wax, usually 5-6 months, and are resistant to the elements. The latest polymer technology allows paint sealants to give the similar gloss, depth and shine of a carnauba wax.

 

Thank you for your reply Met. I want to get everything right but it appears polishing on is quite a task as I don't have a DA for now anyways. Am I correct that polishing successfully can't be done by hand without tons of elbow grease. ? I just bought $300 on towels, wash mitts, nanoskin, coatings...damn, I don't want to cut out a step but I just want to get the winter crap off asap and get the paint protected until I can do a complete job later on. It's been a long winter and can't wait to get started when the weather improves.