1. The limit on the total of Bitcoins that may ever exist is, numerically speaking, much too small compared to the world money supply, which leads to a significant psychological barrier - since it is very difficult for a normal "man on the street" to believe that 1 BTC could someday be worth $100,000 or more (as it would have to be if Bitcoins ever became as widely adopted as the US dollar, say).
A dollar is divisible to 2 decimal places ($0.01). A bitcoin is divisible to eight decimal places (0.00000001). If you express the total number of bitcoins to two decimal places, you get 21,000,000,000,000.00 (21 trillion).
Exactly. Let's call it Bitcoin 2.0, with 7-letter currency symbol "satoshi". There will only every be 2.1 quadrillion of them. Then the common man can really get behind it.