Keep in mind that adjoining surfaces that are clamped together never precisely agree in fit.

Carbon paste therefore has three purposes:
1. Increase resistance to shear creep...increase static friction between surfaces allowing a lower clamp torque for same clamping strength aka PSI.
2. Paste fills voids due to lack of part agreement. Micro-fissures between matching parts are filled thereby increasing clamp surface area. Pasted is incompressible and therefore acts the same as a hard surface when captured in micro voids in mating parts.
3. Prevents stress corrosion if parts aren't the same material.

Its great stuff. I use it where ever carbon parts are present that require clamping...carbon on carbon and carbon on Al...as in the case of carbon handlebar with alloy stem.

Hope that helps.