Math Is Hard said:
why is a nickel twice as big as a dime if it's worth half as much?
The nickel is large because it is on the verge of splitting into two dimes by asexual reproduction. It's worth less, before it splits, because it is younger and less experienced.
Speaking of coins: once, when I was at work surveying some ancient ruins that were to be mapped for historical research, the ground beneath my feet suddenly gave way and I found myself sliding down an inclined shaft away from the sunlight and into a dark, cool, stale, mysterious place below. Whipping out the 2000 watt flashlight I had ordered through the
Coast to Coast program, and which I always carried with me in broad daylight, because it is also a radio, I quickly flicked on my favorite station, and sat down to wait to be rescued. After an hour or so, my eyes became accustomed to the dark and I began to make out the figure of what looked like an old woman huddled against the wall of the other side of the chamber I was in. Soon it was clear she was engaged in some knitting. Later it could be discerned that she was knitting something I couldn't make out. Later, it was completely clear that what she was knitting was totally obscure.
About an hour later, she uncrossed her legs, and nudged at what looked like a heap of indeterminate properties that was on the floor of the chamber in front of her. "Penny! Penny! she said, "Wake up and try this on, now!" The heap stirred and elevated itself from the ground, and revealed itself to be a weird, purple jellyfish. She held the garment for it while it sleepily slipped it's tentacles into all the tentacle sleeves, and then she buttoned up the front. "Looks pretty good!" the old woman said. The weird, purple jellyfish just yawned. Why is it that a quarter, which is worth five times as much as a nickle, only turns up like a bad penny, when the nickles are wooden, since if you bite a doubloon to make sure it is really gold, that's a pretty penny in dental work if it turns out not to be, but if a pennywise jellyfishfoolish fool bites a jellyfish, he will have no pennies saved for a rainy day because a jellyfish saved from cold on a rainy day with a nice sweater is money in the bank?