Why was the 2-foot model built?

[Mott the barber]

My favorite shot of the 2 footer (and one of my favorite shots of the ship) is the rapid tracking shot of the ship going to warp, first used in EAF to try to escape the Q grid. Doesn't look so hot in Where Silence Has Lease on S2 blu ray, but I'm betting CBS-D will make it lok good again like in EAF.

 

[Tosk]

They used it for the whole time (minus the occasional CG shot)

There's just the one CG Enterprise shot in GEN, I believe. Going to warp after the scene in stellar cartography.