Landfill requires area. Plasma gasifier produces energy. Here's all the motivation why.

I don't think that's quite a fair comparison.

Option A: Con, landfill space.

Option B: Pro, energy generation to burn. Con, energy cost of capturing carbon. Con, storage space of captured carbon.

I think to be truly fair Option A has to consider the energy generation you will have to do elsewhere to make up the difference, which may or may not be carbon neutral - or to flip it, the energy generation you won't have to do due to Option B. So it really depends on the energy generation landscape you are within.