How many silicon atoms is that?

The funny thing is, it doesn't matter. "2nm" is just marketing; nothing about it is actually 2nm in size. But that's okay, because that was true at 7nm and 14nm and even at 28nm.

So what 2nm really means is "better than 3nm".

Why do we all go along with this charade? It’s so silly and unscientific. Why can’t we just call the things correctly?

It is the same reason why we use millimeters of steel as a measurement of the armor performance of tanks even though they use composites of different materials.

Because it is easier to compare two numbers even if they are meaningless in reality.

It would be better to stay quiet instead of comparing things incorrectly.

there is no correct single number to use

SRAM density is a pretty good single meaningful number

Isn't the smallest trace/spacing 2nm? Most is larger but 2nm is possible for some traces/spaces.

A silicon atom is 0.2nm.

As many as you want.