Modular or Sidemount only rig
It is not a fad! It is here to stay! Sidemount diving has been used for decades already and in the harshest environment imaginable. So NO, it is not just a fad.
For the last two years now there’s been a surge with manufacturers to introduce sidemount compatible wings or other BCDs. No blame, just to say that everybody is jumping on the bandwagon, that’s it!
Diver using Sidemount configuration
Essential Scuba Training 