I refuse to use those backstab connections when replacing outlets. Hate those with a passion, and thee's actually a good reason to. I haven't come across those Wago connectors yet in any residential wiring, the last light fixtures I replaced in my house all used wire nuts. I have encountered a variation on the backstab connection - it wasn't a self-gripping thing, it was simply an alternative way to insert the wire to be held in place by the screw on the side, which clamped down on the wire with as much metal in contact as you get when wrapping the wire around the screw. Sad that it has to come to this, but it seems too many people haven't a clue as to which way to wrap the wire around the screw.
When replacing failed outlets in my house (usually the cheap ass stuff used in the original construction fails to hold the plugs as the contacts lose tension, or in a couple of case, the whole plastic cracked off - seriously I wonder what some people do with their corded appliances), I NEVER use the cheap bulk packages, I always get the higher grade ones, they cost more but are far more robust. And if it's work I'm having someone else do, I specify those type, not the cheap contractor grade garbage. Or I'll buy the things rather than have the contractor get them, so I know they are using the good stuff. This is a far bigger problem than the type of plug or the voltages used or whatever - the hardware comes in all levels of quality from "you're really trying to burn your house down, aren't you?" to "Hit this with a sledge hammer and it still maintains integrity and protection from shocks". It's all a matter of how much you are willing to pay, like most anything else.