I have 3 esps. Do I use one, or all 3?

Why 3 files so small and not combined?

The ESPs are dummy files. They're just there to load the BSAs.

Each BSA contains a different category. I'm unsure which category each BSA represents, though.

Derp~

That should have been obvious. Thanks.

Edit - Question for the general audience:

Any idea what each category is?

I'm not completely sure, but two of the packs were released for the vanilla game, and the third was released after Dragonborn's release and mostly contains textures for the DLCs (though I think a few vanilla textures are included as well).