I'm not a knife maker nor am I an expert of any kind, but on the specific design of the Lil LionSpy, wouldn't a phosphor bronze (metal) washer eventually dig into the G10 thus causing blade play?
I'm just saying that PB washers arent always the ideal choice.
With traditional designs and methods of operation, I agree that PB washers are better long term.
If the part of the whole point of the knife is to be different, such as by having a solid G10 side to the handle, then other things need to be considered too.
I'd be surprised to see Teflon washers on the SpyOpera. Again I'm not an expert, but I dont see an obvious design reason to use Teflon.
I am curious though what's in the SpyOpera.