But TFA justifies avoiding the attribute because it "often leads to unnecessary code duplication" which is irrelevant "if it is only applied in one specific pla

But TFA justifies avoiding the attribute because it "often leads to unnecessary code duplication" which is irrelevant "if it is only applied in one specific place across the entire site". It also mentions CSP as a reason to avoid the style attribute; can anyone explain what this means? Is this actually going to have a practical effect, and what does an inline style attribute have to do with security policy?