Or do more people buy the power amp to get better control, refinement and power in reserve to enhance their setup at the same listening levels.
That would be the camp that I'd count myself towards. And it's precisely what I got from my Tyrs.
But in the case of Tyr, I don't think you
should shop for one because you're looking for power. If power is what you want, dual-Vidars actually get you
more power than you'd get with Tyrs. (Mono-Vidar is 400 Watt RMS into 8 ohm, Tyr's "only" 200 Watt RMS into 8 ohm.)
Instead, as far as I'm concerned, you should shop for Tyr for one of three reasons only:
a) because it's based on a choke-input topology instead of the usual capacitors, which means that you're looking at a much "faster responding" amp, which gets you more detail than you could ever get with a Vidar
b) because you want to drive lower-impedance speakers without running into overcurrent or temperature protection left and right
c) because you've got some money to burn
…or any combination of the three.
For me, it was a combination of a) and b). I don't need more power for my system, my dual-Aegirs were more than enough in that regard. I never listen louder than about 85, with the occasional peak to 90dB. What Tyr does for me is the detail delivery and the fact that I no longer have to worry about my low-ish (dropping to 3.2 ohm) impedance speakers being plugged into mono blocks that aren't really officially rated for anything that drops that far below 8 ohm.
If all you want is power, I'd go for dual-Vidars. They're cheaper, require a lot less real estate, and deliver more Wattage into 8 ohm.
For everything else, you can't go wrong with Tyr.