Nah, I want 10k because its a nice round number for calculations.
What about other fiat currencies? Euro, Pound, Yuan, Yen, price of BTC is different in each of them.
Currency exchange calculations will never be unified and easy.
No, but all shares, assets and other holdings are usually denominated in USD, even though the others are still major currencies.
Obviously no one is going to buy in saying "if we can just get to $10,000, the calculations about how much profit I've made will be so much easier!", but it's nice to be hovering around $1000, drifting far away is great but it's annoying when I'm doing maths.