Collimation is important for any telescope, but much more so for SCTs.
The reason is the magnifying effect of the curved secondary in SCTs. For ordinary reflectors, a small change in the alignment of the mirrors has a correspondingly small change in the final image. But in SCTs, the secondary typically acts as a 5x magnifier, so even small changes in alignment translate to large changes in the final image. The primary mirror is aligned at the factory and the telescope must be returned in order to realign the primary. Adjustments to the secondary are made using the three Phillips head screws in the secondary fixture located at the center of the corrector plate in the front cell.