I don't know where all those wild theories about not enough spring pressure and wire deformation come from. The technology is successfully in use for decades, these terminals from quality vendors usually have a huge collection of independent worldwide approvals and very reliable ratings. It's not rocket science. The WAGOs are even UL listed, and that's what you look for when you buy products for the little electrons usually, isn't it?
Other means of connection are good and valid as well, of course. Someone capable and experienced with screw terminals or twisting nuts will probably do just a fine job with those things as she or he would do with spring terminals.
Two extreme examples next to each other, just because I enjoyed doing it and describing it, to get my head off work.
Left: Will last for a hundred years if you ask me, if you keep it away from water and amateurs.
Right: Home handyman's proudest hour. Still telling his grandkids how he himself has proudly shown those wires for the electrons their place! Doesn't have weak writs at all! And knows that you don't stop twisting before the thing you're working on starts to squeal. Doesn't know nor care about it being completely dry (no contact grease applied, of course). Then another turn... Will glow soon. Will break down at some point in the future. Congratulations on a job well done.
Installations like the right one have been done by private people and even some professionals in east germany quite often before the Wende and even after. You regularly find it melted down even under moderate load. That's why Aluminium is now forbidden for new installations for diameters <16mm².
Aluminium is delicate. It tells you a lot about quality of work and quality of material. Because unlike copper, it doesn't forgive, it doesn't forget, and it will put your house on fire if you don't know what you're doing. :-)
Where the wire deformation business came from was conversations with other engineers who knew a helluva lot more than me who took the time to explain it; the actual contact surface of a round solid copper wire is small. Flattening it, even a few thou, under a screw greatly increases the contact area.
I'm sorry; I don't agree with your assessment of WAGO's longevity. Decades of success with a new technology means precisely dick. We have decades of experience with glyphosates and neonicotinids, and while they do create more food per acre, they're turning the global food supply into a carcinogenic nightmare. But hey, the guys Monsanto put in charge of the US EPA say they don't cause cancer, so we can all sleep safe now...
Like I said; an honest skeptic.The one value you did get across, however... I cannae argue. A moron can likely install those and get results which are as safe someone who actually knows what they're doing.
I still remain unconvinced that is a better end-product than what can be produced by someone who knows how to use Ox-Gard and screw terminals, however.
mnem