Stopping air leaks from the exterior is only part of the story. You also need to stop warm interior air from hitting the rim from the inside and condensing there into ice and feeding mould growth on the fibrous insulation in the rim. Do those bags create an air barrier to inside air? How are they affected by moisture?

If you wouldn't blow in netted cellulose to rims, is there a difference if you put it in a bag?

Not for me. Afraid I'm a fan of spray foam, even when you are required to cover it with a thermal or ignition barrier.

Thanks worthy. I very much appreciate your opinion. I did not think of it that way. I want to spray foam the areas but am so concerned about the horror stories I have read about off gassing.