Editing .mts files in Vegas

I am happy editing .mts files out of my camera on my pc as it is quite powerful and I have no issues with lag or stuttering on the preview window.

I was under the impression that working with these .mts files was me working with the raw files out of the camera so I would be obtaining the best quality possible.

I have since read alot about intermediate codecs like cineform neoscene where people are converting their raw .mts files into cineform avi files first before then editing in vegas.

Would doing so improve the quality of the image or just help with the editing within vegas?