[8note]

Carbon dioxide has a low concentration in the atmosphere, the atmosphere is really big, and diffusion is not a particularly fast process.

Adding to that, industrial processes tend to be big and heavy, and also take fossils fuels to make. Even the outputs of these processes are measured in tonnes of carbon

No less, whatever format you're storing the carbon in will be very energy dense, either via compression, or by chemically removing the oxygens.

So, there's limits to how quickly your apparatus can interact with new carbon molecules, on moving it to new carbon molecules, and on making sure the products of you apparatus stay sequestered.

If they're thinking they can scale, it's by setting up on top of carbon emitters, but doing that is net carbon positive(some will leak, and carbon emitters will continue to scale up), rather than negative