What is lost if DeFi were more heavily regulated or outlawed? What is lost if shipping were more more heavily regulated / outlawed?

Ultimately we have to do many things, and solutions aren't mutually exclusive.

Getting people to agree on "low-hanging fruit" is very difficult. Even on here you'll see people that are fine with using energy on crypto. It'll be an even taller order convincing folks that shipping should be outlawed or tightly restricted, especially folks living in rural car-dominated areas of Anglo countries. Then you'll have to mount a new fight to convince people to heavily restrict the bath and restrict shower usage. Oh and keeping your lights on all night. Then start a campaign to restrict running the AC. There will undoubtedly be folks who'll try specifically to find holes in restrictions as well, such as buying a propane stove on areas where gas stoves are banned, then you'll need to amend all of these restrictions and burn ever more political capital.

Much simpler to tax energy based on emissions. If that means PoW crypto will never be profitable, then they can pound sand. That way you also won't have lobby groups grandfather weird exceptions on restrictions to preserve their precious market.