Right as Narc was posting, I had a bit of an epiphany for another way to use this. Anyone who's used LogisticsPipes with BuildCraft and IC2 has probably noted the occasional (but persistent) annoyance of needing a way to smelt, grind, or otherwise machine-process an input on-demand. A recipe for stone bricks, for instance, may need to smelt the cobblestone from your quarry into the smoothstone it needs. Or your recipe for machine blocks may be blocked by a lack of refined iron even though you've got stack after stack of ordinary iron handy.
There are ways to solve the problem. You can pre-fabricate some of the target material (though doing it automatically gets hairy). You can use a satellite crafting pipe to turn an entire bank of machines into one moderately-slow "crafting" operation. Or you can just do it by hand whenever your request gets denied. But all of the solutions are just... eh. None of them really feel like true solutions, just workarounds.
Enter liquid UU and a custom machine (or some form of extension of existing ones, a la the hopper). For a small (but significant) amount of liquid UU, it allows you to perform the operation instantly, meaning that a simple crafting logistics pipe is all you need. Raw materials come in, the internal UU tank goes down a bit, and the final product pops out immediately.
For numbers, right now we're looking at 0.002 UU per smelt, or 0.003 UU for any other operation. Assuming your mass fabricator doesn't have scrap, that works out to an effective cost of 2000 EU/smelt or 3000 EU/other operation. (With scrap, it's 1/6th of that, plus 0.07/0.10 scrap.) Not sure if we like those numbers yet; we'd probably have to see it in practice first.