I use elastic shock cord for nearly everything.
However, I like to use either wire cable or Kevlar to attach deep inside the body tube, come out to the front end, and THEN attach the elastic shock cord. Here's the wire cable shock cord mount for my recent 1/45 Little Joe-II build:
I'll be attaching 1/4" elastic to it, many feet of it.
One problem I have with the old-style methods of gluing a mount to the inside of the tube, is that it is a jamming restriction. Chutes sometimes get stuck if they are not packed tight enough to slide freely enough. I'd rather keep the tube smooth inside.
The other problem is when the old cords get worn our, scorched, brittle, etc. It's a huge hassle to try to remove and replace a mount glued to the side of the tube. I have not even tried to replace one. I gave up on those methods before my 10th rocket, after my most successful early reliable rocket (MPC Viper), broke its shock cord on its 10th flight. Just before it flew, I saw how badly worn the cord was, but being glued 2" down inside of the tube, there was no way for me to fix or replace it. So I flew and hoped it would hold.... it didn't. I hated those mounts ever since and never used them again.
That is the benefit of the wire cable, or Kevlar, being mounted in deep then attaching Elastic to it, it is very easy to replace the elastic. The wire cable never wears out. Kevlar.... could, it depends on the size, hot it is attached, and how exposed it it to ejection heat. For example D12 ejection charges will fry 100 pound Kevlar, but I've not had an 18mm motor burn up 100 pound Kevlar (yet). Still I try to minimize heat damage to Kevlar, if I attach it to a front centering rig, I will add 2" or more of heat shrink tubing over it where it is most exposed to the ejection charge as heat protection.