Bitcoin does use a lot of energy but so does Google, Banking, or Xmas tree lights but it is not that much considering the value it provides. Besides, it is a great way to use stranded energy that would be lost otherwise. Also, the energy doesn’t grow exponentially like its price and more efficient machines are coming to the market which will reduce the electricity used per coin.

The volatility is not ideal but it is the price to pay for an asset that goes from zero to $50k in 13 years. Gold was very volatile 200 years ago and then became more stable. Bitcoin will probably do the same in the next 10 years.

Bitcoin exchanges get hacked all the time. you have to be very picky about the one you use, go for the biggest and the oldest and your money will be safer. But as Bitcoiners say: not your keys, not your coin. When you have a sizable amount you should put it into cold storage where it can never be hacked