Help me refute my economist Professor in claiming BTC is not good as currency.

I went into a heated argument with my professor the other day about Bitcoin. His theory is as follows:

"Currency should be treated as a unit of measure. pretty much like the mile or pounds. We use these units to measure weight and distance, and we use the dollar to measure value. Imagine living in a world where there is a defined, pre-determined unit of miles, we wouldn't be able to measure distance. Units of measures need to be infinite to be feasible in measuring distance, dimension, and value."

He continues :

"Take gold, for example, as it resembles Bitcoin in being scarce and difficult to produce. Gold was the reason for the depression because that was an era of industrial revolutions. Countries' GDPs were getting high and the source to measure value, gold, was in limited units. So this medium of exchange could not keep up with the increasing products in circulation, therefore, prices of products and services decreased."

Here is my counter-argument:

If the issue is that we need enough "unites of value measure" then a single bitcoin can be divided into 100million units. if we take all Bitcoin in existence (21m) and multiply it by the smallest unit of a bitcoin (100m), we then have 2.1 quadrillion units. All money in existence today is worth 500 trillion. Bitcoin, if a single sat is set to one dollar, is enough to liquidate the global economy 4 times.

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Please share your thoughts on my counterargument. I tried not to bring up other points but use his analogy against him.