When using MPC-HC/madVR, you can only play unprotected content. Atm, AACS 2.0 discs can only be played through licensed players like PowerDVD.
So basically in order to use madVR, you have to rip your discs first, or use some other method to unprotect the discs. Unfortunately for UHD Blu-Ray there's no solution for ripping available just yet, but it's probably only a matter of time.
If you're willing to use PowerDVD as long as ripping UHD Blu-Ray isn't available yet, then it makes sense to aim for Intel SGX etc compatability. However, if you plan to only use madVR, then Intel SGX and HDCP are of no consequence.
The 1080Ti sure is a powerful GPU. Using that will allow you to use very high quality upscaling algorithms when playing 1080p Blu-Rays. Truth be told, probably a 1070 would already suffice. Or even a 1050, if you can live with some small compromises. But then, if you have the money, having some extra GPU headroom might come in useful for future madVR algorithms.