To be fair, carbon capture does not have to entirely offset all of global emissions to be useful, it only does if you're trying to use it as a single solution to climate change by itself. But if you were using it to augment a reduction in emissions you'd need less of it, or if you do eventually reach net zero global emissions someday, but want to slowly reduce carbon already there to bring the world back to the temperatures that used to exist, you could do so more slowly as a long term project.