The CO2 from methane breakdown was sourced from the atmosphere in the first place. And it goes back into the atmosphere. It's part of the permanent surface-atmosphere CO2 cycle.

Atmospheric CO2 -> Grass -> Ruminant animal -> Methane -> Atmospheric CO2

Fossil fuels, OTOH, bring up CO2 from deep in the earth where it has been sequestered for eons.

If we ate less meat and turned the pasture into woodland, we could sequester quite a lot of CO2 on the order of 50 years or so. Longer if we buried the wood. And I'm not against that.

But it seems silly to me to focus on these minor hacks to surface cycles for temporary gains when the clear long-term problem is fossil fuel. We need to keep focusing on fossil fuel.