The intent of this form of particle is to introduce more customization and flashiness that ISN'T more hat/taunt unusuals effects, something that we have in abundance.

These do not affect your frames. Although it may introduce additional particles, it has been tested through gameplay to not impact performance.

Ideally yes, Valve would implement this submission with a Smissmas restriction, mirroring a Spell's Halloween restriction.

That is entirely up to Valve’s choice, we workshoppers do not control how an item is implemented. It could be through unboxing, contract rewards, MVM missions, a free gift, who knows!

This Miracle replaces the Spy's disguise smoke with a blizzard effect, with wind and snow.

Spy Cosmetics