What is "fusable interfacing" and who uses it to make kilts?

[sydnie7]

I'v seen it called by the brand name "Stitch Witchery"
I have female friends who use it to change the length of slacks and trousers depending on the heel height of their shoes.
It works better on Light fabrics than Heavy kilt fabrics.
I carry a foot or two in my travel kit along with safety pins, and needle, and thread, for emergency clothes repair.

Stitch Witchery, Steam-a-Seam, and similar variations are not the same as the fusible interfacing of the original question. They are just a layer of "glue" that is activated by the heat of iron to stick two layers of fabric together.

These products are all about the fusing, and result in little if any interfacing or stiffening effect. This is by design -- you wouldn't want a stiff hem, generally speaking. They are very useful (see Barb T's tutorial on making flashes, for example) but they are not interfacing.