One of the ways we've used rivet nuts recently is to fasten our bumper frame to the chassis. On opposite sides, we have four 1/4-20 bolts spanning through the c-channel, 2x1x0.1 tube spacers, and into the threaded rivet nut.
Here is a top view
Here is a better angle
We also use the hand tool. We keep all of our rivet nuts in a special box with the gun.