Isn’t that kind of apples and oranges?

Market cap and GDP are both measured in currency units, I guess they have that in common, not sure I understand the usefulness of this comparison.

To me it’s more about the scale of these numbers. After billions, people (like me) kind of lose intuition about how gigantic these numbers actually are. Yes GDP has time in its unit, but it still gives a general idea of the size.

GDP is more like a currency/time unit, though.