Never used them. I never cared for triggers at all. I preferred PS1/2 style shoulder buttons that were just normal buttons. The PS2's were pressure sensitive but they still sat flush with the controller surface and hardly anything used the feature anyway.
My current PC controller has flush shoulders too. I'm actually quite the fan of the controller. It's a ZD-V, with the stupid dumb Xbox button names but the symmetrical PS-style layout. I was adamant about both of these features because, well, let's face it AAAs are too damn lazy to spend like five hours identifying your controller and making the onscreen button prompts match (with the exception of a handful that will do the PS layout but not the SNES).
Anyway, I'm not opposed to the idea. In fact, it sounds really cool and I'd love to try it out. But the PS5 doesn't have a single game of interest to me that I can't get on PC, so I haven't bought one.
There's a difference between canon and not-stupid.