take for instance a gfci or rcd fault that you are tracking down... you have found the first outlet in a radial, and now need to find where the fault is... if you have twist nuts and have all the outlets spurred, then you have to undo one, hook it up without the outlets further down the radial, test it... if it works, then hook back up the rest of the radial, test it again..it trips, so you move to the next outlet... and do it again...
Wagos allow you to simply trace which cable is feeding the outlet.. pull one ground and neutral out of their wagos, test, plug them back in, test again... about half the time per outlet, each time...
When testing for faults, it takes me less than half the time to test and track down faults with wagos than with the wire nuts when spurs are used... but when simply screwed in series where no wire nuts were used, then no wagos are needed either...so no savings either way.
Now, for the ground connectors, I use the wire nuts. If I am capping a neutral in a switch box..I use a wire nut. Hanging a fan light with those funky twisted strand wires on them, again, wire nut... dont like to but the connection just does not seem the same in the wago...
But most of my Solid work, especially on my outlets where I like to parallel... rather than series... Wagos please...