He probably meant swap frames and move over all the components.

I may be wrong, but isn't the purpose of the seatpost cutout is shortening wheel base, so you can slam the rear wheel closer to the front, making for a tighter handling? I've wanted an aluminum frame in the past, but I've grown very attached to my steel in the last few weeks. I feel like while preserving ride quality, I would rather work on a lighter crankset and a rear wheel that I can actually change the cog on. Once this thing is perfect, I plan on either buying an off-road all-weather beater, or a "nice" aluminum tarck bike.

n+1, a never ending cycle.