Important note

This build uses the arcane [Frost] squall helmet to [Reach] 251% power strength WITHOUT [Blind Rage]. For this reason, [Corrosive Projection] is not used as most enemies will have no armour. This necessitates bringing duration back up with [Continuity], so they keep their armour strip for long enough to kill them (it comes back when the freeze ends)
This allows [Frost] to have max efficiency 100% armour strip avalanche. This is a very specific build, mostly used for grineer or casual content.

300 plat for a hat is not exactly nothing.