Our two cats get supervised time in the backyard every couple of days - we used to put them in harnesses until we moved to a place with high enough fences that they couldn’t get out even if they wanted to.
Mostly they just wanna chew grass for 15 minutes and maybe investigate a random plant bed, and they quickly learned that if they come back inside when called they get treats :)
Even aside from the temptation to use offsets to kick the can down the road for reduction targets, the rampant abuse of carbon credits make this absolutely the right decision.
Relevant viewing: Wendover Productions: The Carbon Offset Problem