I hate to break it to you but all financial ratios and metrics are simple mathematical calculations.
Ever heard of EPS? P/E? PEG? These are valuation metrics utilized everyday in the investment community.
If market cap meant "squat diddly" then why do you see it used so freely in the investment world? Why is it even a metric mentioned? Why are there categories of stocks based on market caps? Why are their ETFs based on the size of the company?
Why did the world make such a big deal when Apple became the first company with a 1 trillion market cap? Then when Microsoft hit it in April, why was it such a big deal?