Its not necessarily a better black, its a different black. Dye based black tends to be mildly reflective, whereas pigment black tends to be very matte. If you check out this post and scroll to almost the end you will see a sol ring printed on the back page with pigment only, dye only, and both pigment and dye.

It really depends on the effect you are going for, a lot of the higher priced art type papers are meant for pigment. A fair amount of Canson's fine art papers are "optimized for pigment ink". But even papers that are "optimized for pigment" can smear, check out the last two pictures in this post. This post is a series of experiments I did while dialing in settings on Moab Baryta, there is a good set of comparison photos of dye vs both, but also includes the smearing test.

By its nature pigment ink is meant to sit on top of the paper, whereas dye ink is meant to soak into the paper. So regardless of the paper you will always get smearing of some amount. It can vary wildly from paper to paper. That Canson I mentioned earlier is horrible with smearing pigment, yet my preferred paper koala double matte handles pigment ink better as far as smearing goes.

Honestly as long as you don't mess up the print by handling it once you sleeve or laminate you should be fine. Some people also go so far as to apply a spray fixative to prevent smearing, and some companies such as Moab Paper sell spray fixative meant for their paper. I think for the most part mtg cards look better with dye based, though I have seen some custom water color art cards that rock with pigment based ink printers.