I don't know if you've tried to use those next to lots of rifle fire, but they don't work that great. If we're talking about their ~$40 passive earplugs, the sound reduction isn't sufficient for rifles, even with a perfect fit. You're still over 145dB after the earplugs. It's explicitly not for use with gunshots, it says so on the box.
If you're talking about the active ones marketed for shooting sports (which incidentally don't block all frequencies equally), it's okay reduction for outdoor rifle (still painful for indoor rifle). It's much more passable for pistol than super loud rifles (let alone artillery/etc).
Plus those are $300 a pair, and the 3m plugs in question were what, $10?
Edit: Also the difference between $200+ custom molds and plugs, vs foam ones that need to cost a few cents each.