This makes enforcement simple.

Setting emission thresholds means needing to get out there and perform spot checks in the field. It's specialised, expensive and in practise means many people just flouting the law and getting away with it. Pointless law.

Simply banning ICE strimmers and blowers means any enforcement officer can easily cite rule breakers, confiscate equipment, etc.

And per sibling, not the same as mandating one technology, at all.