Mainly because we can manipulate it's shortcutting effect over this universe. What i mean, is wormholes. The theory is open to debate, but then we might already have something similar in this universe, right at this moment. Black holes are considered to be rips in space-time, which suck in matter, send it down some tube or something, and then down to the singularity where it is destroyed.
Some people think that matter gets sucked through a black hole and then exits through a white hole.
What i believe black holes to be, are links from this dimension to a lower dimension. Perhaps the 1st or 2nd. Again, it's open to debate. To sum that up. So perhaps there is a form of energy we haven't found yet which could be used to force space-time to create a wormhole to the 4th dimension.