Spider web is sticky, isn't sticky too? What could they need a sticky fabric for, catching bugs, like fly paper?
You never heard of the "fly paper strategery?"
Actually, spider silk comes with, or without stickiness. In a common spider web, the support strands are stronger, and not sticky. It's the little lines in between that have stickiness.
Many spiderwebs also have ultraviolet light pigments, to make them look like flowers in ultraviolet light, and catch more unwary insects.
The fabric applications are for the stronger, non-sticky strands.
Now, the next question for you is ... How do I know all this stuff?