As long as mining pools do not use knots by them self, there is little effect. Knots may not accept "Spam" blocks. On the other side, pools will not switch to knots, as "Spam" means more tx hence more fees. A problem could be the loss of core nodes and the decentralization. As a node runner I actually do not want all this Spam filling up my disc.

Bitcoin fixes this https://www.change.org/p/tell-mastercard-visa-activist-groups-stop-controlling-what-we-can-watch-read-or-play

Like the prusa 3d printers