If our currency was printed in exponential denominations ($2, $4,...$1024, $2048, etc.) it'd be real easy to pay for your sixth, seventh drinks even if you were smashed. Tipping 10% might get a bit complicated, but I know I'm not throwing in an extra
$102.40 on a $1024 drink!

Two problems with this: (1) Happy hour -- So much cash, so little time. and (2) Promotions -- like in, "with every drink ordered you'll receive a ... " Damn! How happy can I be?

But currency at the moment comes as 1:
2:5:10:20:50:100....etc (from 1p up to
£50, or maybe beyond). (Actually yhis
may not be true for US currency - is it?).
<>
This is not quite optimal, but is close to
optimal and more convenient, and you
need fewer different types of coin.

1:10:100... that would be "base ten" numbers. We live in a "base ten" world most likely because we have ten fingers (gents could have imposed a "base eleven" system but that wouldn't be fair). You can't raise one to any exponent to get ten. Binary is based on two to the N power (like my sexual stalling tactics, ahem!) where the maximum number of different values expressed would be two to the N power where N is the number of bits to store the value.

Okay - good for sliding scale drinks, screwing, and not much else.

//You can't raise one to any exponent to get ten.//
[NG] You need a modicum of math here: 1 10 100 is 10 to the 0 1 2 power, just as 1 2 4 is 2 to the 0 1 2 power. Same thing—both are exponential.