I could see them trying to make the claim that it is good for the environment because there’s a lot of metals that go into those engines, and I’m sure that recycling them isn’t really feasible in an environmentally friendly way. To add to that, it depends entirely on how they change out the fuel systems and such but that may not even make up for the cost of running them.

There’s also noise pollution to consider (assuming they actually switch the fuel to something renewable, which I will press [X] to doubt).