It creates ('faith based') money, therefor people are willing to give up resources.
All that effort helps to build a trust in the network.
The perception of value of a BTC will grow, when you see how much it costs you to generate a new set of 50 BTC.

All in all: it isn't a waste of energy; not more than the energy/time needed to keep enough trust in the value of bank accounts in EUR or USD (who have the rather large 'advantage' that you can/must pay your tax with them).

At the current price level of over USD 10,- it is better to mine if you can have the room and the possibility to deal with the noise + heat from the mining rigs. (Best if you use the heat to warm your house, not when you have to extra-cool with air-conditioning.)

If you do not have the cash to buy a stack of good GPU cards, you certainly won't have enough cash to buy BTC on a level which makes trading worthwhile.

You could buy small amount of BTC in the hope it will raise in value, if you can transfer your (legal tender) currency cheaply to an exchange. Do count on it though as a pension plan

Hi all,
I am CrazyNick. I started mining about a year ago and started trading when 1 BTC reached USD 20.
Given the current level of difficulty I stopped mining (don't have enough GPU power).