My experience with the marketing speak around process nodes.
1) In the way back times, (think Intel 8080A) the complexity of the chips was advertised in "logic gates". More gates = more impressive chip.
2) But logic gates weren't equivalent from one process to another, and so it switched from "logic gates" to "transistors." More transistors => more impressive chip. (this is when I left Intel for Sun Microsystems)
3) But not all transistors are created equal, and there were things (like copper metal layers) that made chips better even it it meant you couldn't fit as many transistors so "line size" was what was important. Smaller line size => more impressive chip.
4) But now people had redesigned transistors so that they could be packed more densely and the limiting factor was how much silicon you needed for the gate (NMOS/CMOS) and since that wasn't a whole transistor, it was just a "feature" of the transistor, "feature size" became the new marketing term. Feature size was measured in nanometers and so the smaller nanometers implied more features per unit area.
It has all evolved over time so that it is harder and harder for any sort of comparative analysis between processes seems to make any sense at all these days.
These days, much like the TSMC presentation that is excerpted in the original article, semiconductor fabs rely on comparative measures like "same stuff would be size on this process vs size on the previous process." All the really interesting parameters to me are things like how that effects leakage (thus idle power) and voltage thresholds (thus idle power and maximum frequencies).
I'd love it if there was some sort of SI unit you could demand which would give you a better comparison metric but I don't think we'll see that. Everybody wants to be "the best" and that is most easily achieved when you can dynamically define the metric for "best."