many years ago, when radios, airplanes, and pilots started getting better, some people decided to do away with their rubber bands and switch to bolts.

The idea of using nylon bolts was originally so that they would break on impact.

The idea didn't work.

Today, most people still use Nylon bolts simply because they won't vibrate loose like a steel screw/blind nut can.

I can't recall EVER seeing a crash where wing bolts failed in flight.

Here's a Strength chart: