Buying bitcoin is itself an investment and the most secure, most investments inside bitcoin are scams, btcjam has defaulted many loans so be cautious and just buy more bitcoins
ANXPROThat's very shallow approach. Luckily for many is a bit more than "buy cheap, hold and sell with profit".
If everyone applied that logic, bitcoin would be dead by now. Who would give a shit about the currency no one uses (everyone just hold, waiting for the right time to dump)?