SilkTest Question:

Answer1:
SilKTest is not a load testing tool - it is a functional testing tool. You could do a crude load test by having Silk on multiple boxes and then running each one at the same time - but that is very crude.
You need Silk Performer or Load Runner or some other load testing tool for doing load testing.

Answer2:
Do some performance testing on a local binary.
Imagine trying to load ten large files into a word processor or text editor manually. If the procedure is to load one large file and when it has loaded load the next. If performance degrades after each file has loaded. The first file takes 30 minutes to load, the second takes 75 minutes... This is a perfect candidate for using SilkTest (or another functional GUI testing tool) to perform It won't get bored waiting and it will be ready to load the file as soon as it reads the "Ready" status.
You could run a series of image transformations in an image editor, recalculate a budget for a large company in financial package after changing a few variables, edit a style sheet in a page layout and then scroll through the document, search and replace a single letter in a large text file, etc..
There are a lot of other single unit performance tests that can be run using SilkTest--use your imagination.