Yeah, but how vague is that? You have a link interface. Ok. And it's scalable. Ok. SO what's it a link interface for? Why should I care?
You say that like you have NO context at all for the term SLI.
Some would say that it is a sign of the times. Computer manufacturers try to obscure more of the technical details to the consumer, or certainly don't go out of their way to inform.
The reality is likely this:
SLI was an acronym that NV wanted to use for nostalgia - they knew gamers from the voodoo days would recognize the acronym, and that it denoted technology they were likely SOMEWHAT familiar with (parallel processing for their 3d graphic rendering).
However, despite your contention that this is the same technology, it really ISN'T (I must admit I am not that savvy when it comes to gaming, so graphics cards are not my thing. I did some research).
For one thing, Nvidia has Split Frame Rendering. SFR IS similar to Scan Line Interleaving, but works in a more intelligent and dynamic fashion based on frame composition. IF this was the only algorithm they used, I could see them keeping the OG "SLI". However, they also have Alternate Frame Rendering (AFR) which does exactly what you would guess, as well as SLI Anti Aliasing (AA).
Thus, to use SLI as an acronym for "Scan Line Interleav[ing]" would be factually inaccurate, so they made something that (sorta) fit.
souce:wikipedia, of course.