Why would PoW notes degrade performance? The compute to verify a signature alone is far higher then verifying the PoW portion.

Or do you mean on the creation side? If so, determined spammers will eventually do that too raising the stakes of the cat and mouse game.

We will only get so far with simple reactionary filters to low effort spammers. 

 Anyone talking about "degrading performance" sounds glowie to me.

I prioritize censorship resistance over where my loading speeds are at in the modern-day range of loading speeds.

People lived with dial-up once.