My people are taught that it's a fluid, not a fabric. When particles pop into existance, or exist as matter, in our dimensional space their probability function becomes highly localized and creates a "void" between dimensions and a pressure density gradient at that point in space. This pressure forces the fluid of space to flow into these voids and it's this flow of space fluid that creates and explains the drag known to us as gravity.
We are also taught that if enough matter is brought together in a region of space the flow of space fluid into other dimensions becomes so strong that nothing, not even light, can escape the currents. We call these objects deep blue holes. Technically they are black because no light escapes, but we're smurfs and we think we're cool, so since cool blacks are bluish blacks we call them deep blue holes.
I'm pretty sure I got that explanation right. Brainy lectures on and on about it but it's hard to pay attention when the discussion is about deep blue holes... Smurfette sits next to me... droooooool....
I struggle to conceive of a situation where it would actually be useful
It will print an image across multiple pages - something that a surprising number of "better" applications won't do. I hadn't ran, much less actually used, paint in years until my 72 year old largely computer illiterate father told me about this. Now I use it several times a month to "blow-up" web graphics and crochet patterns large enough that my mom can see to use them as guides in her hobbies and crafts.
"No, no, I don't mind being called the smartest man in the world. I just wish it wasn't this one." -- Adrian Veidt/Ozymandias, WATCHMEN