1) More security (especially if you are careful).
If you are careful the security of bitcoin and fiat alike should not be a problem. But if you are dumb you can lose your money and bitcoin alike. Not really upgrade here.
2) Bitcoins are a potential investment, cash is not. Paper currency only really goes down in value, Bitcoins have a lot of potential to be worth more as time goes on.
That is valid point. In theory bitcoins are resistant to inflation.
3) Fast, worldwide transactions at your fingertips.
Yes, but only with people who owns bitcoins. I have friends in many countries but they don't have any bitcoins (despite me telling them how great this technology is).
4) Similar to #3, but it's a universal currency. It's legal in most countries of the world and you don't need any kind of currency conversion to send money to people in a different country than your own.
You don't need currency conversion if you deal with bitcoin users. Again in theory it is great - but only when everyone is using bitcoin.
Moral of the story? We need total adoption to be able to use bitcoins with no problems, globally.