Well, this is one of my pet topics:

• global GDP is 10^14^ dollars but I’m pretty sure we can’t estimate it to the nearest dollar, nor even to the nearest million dollars (nor even to the nearest billion)
• the most precise clock on earth has an accuracy of something like 1 part in 10^18^ but more typical atomic clocks are more like 1 part in 10^12^
• the unix epoch in microseconds has 16 digits
• the most accurately-measured quantity in physics is known to about 12 or 13 decimal places … other quantities in the natural sciences are known to far less precision
• LIGO can measure some crazily tiny displacements but that doesn’t mean it measures them with a huge amount of precision (TBF, I’m not sure how precise the measurements are)

Anyway, the point is that when someone who works in software tells me they need a 38 decimal digits to represent their numbers, I’m a bit skeptical 🙂

Yes, OK, fine, so UUIDs have more “digits” than that, but they’re not numbers, they’re strings, and they’re by nature very wasteful.