Earlier quoted context omitted.
The only reason I've ever cared about watts is that generally speaking 120 watt and 180 watt processors require more complicated cooling solutions. That's less true today than it ever was. Cases are designed for things like liquid cooling, and they tend to be pretty silent. The processors stay cool, and are pretty reliable. I personally stick to the lower wattage ones because I don't generally need high end stuff, so…
wattage doesn't really tell you how difficult it is to cool a part anymore. 11th-gen Intel is really easy to cool despite readily going to 200W+. Zen3 is hard to cool even at 60W. Thermal density plays a huge role, the size of the chips is going down faster than the wattage, so thermal density is going up every generation even if you keep the same number of transistors. And everyone is still putting more transistors…
Sure it does. Reading the rest of your post I think you're more talking about temperature than cooling requirements, but a 200W CPU needs 200W of heat dissipation, while a 60W CPU only needs 60W of heat dissipation. It's literally a 1:1 relationship since CPUs don't do any mechanical work, so power in == heat out.
Keeping temperatures below some arbitrary number does then include things like density, IHS design, etc... But that only matters for something like Intel's "Thermal Velocity Boost" where it's really important to stay under 70C specifically instead of just avoiding thermal throttling.