A lot of the scare stories are coming from bankers, fund managers and city traders. I can't think why, it's not like they have an interest in keeping things as they are?
Definitely. You can lose your shirt on both, but the volatility of crypto currencies means it's not unusual for them to fall or rise 20% or more in a day, for no apparent reason. I've got some very wealthy clients / friends who are happy if their shares portfolio makes 5% in a year
Exchanges are hackable, nomatter how secure they claim to be. Use them to buy and sell by all means (and, unless you're trading to friends and family, or localbitcoin, you have to use them) but don't keep your bitcoins in an exchange long term - move them to a wallet that only you control, and keep that secure. If your bitcoins are held in a wallet at an exchange, and that gets hacked, you risk losing your bitcoins. Unless you (and only you) hold the private key to a wallet, it and any bitcoin balance in it is at risk.