Capturing methane is a good thing. It’s 86 times more potent a greenhouse gas than CO2.The leftover manure is also used as fertilizer. This isn’t greenwashing.
Tying this process exclusively to factory farming seems disingenuous. Cows still produce methane whether on one factory farm or a hundred family owned farms. Factory farming is shitty (pun intended) but capturing methane is still a good thing.
https://www.scientificamerican.com/article/how-bad-of-a-greenhouse-gas-is-methane/