You're right, but it's a lot harder to account for emission reduction, and offsets based on those are often illusory. For example, you might award carbon offsets for replacing a coal plant with solar, when that would have happened anyway just because the economics worked out better. If you're actually removing carbon from the atmosphere, that's not an issue.
As a matter of government policy, we definitely need to focus on reducing emissions, and a simple way to do that is with a carbon fee. But for voluntary contributions right now, it's not so clearcut.
> you might award carbon offsets for replacing a coal plant with solar, when that would have happened anyway just because the economics worked out better
It depends on which organisation verifies your offset, but the big three (Gold Standard, Verra VCS, and United Nations), all require _additionality_. That is where you have to prove that the offset financing is making the project happen, rather than market forces.
It’s not a flawless process, but in many cases offsetting is helping to accelerate the transition away from carbon intensive emitters.
As a matter of government policy, we definitely need to focus on reducing emissions, and a simple way to do that is with a carbon fee. But for voluntary contributions right now, it's not so clearcut.