Unpredictable is good word. When you are in.trading business things can go so smooth and you are making nice profit but very soon this can change and you start to lose or getting nowhere. There is no proven strategy that will ensure you to be profitable all the time.
And if you want to earn some substantial amount you need big starting capital.
for me trading is one reasonable job. trading like any other job. oh yes, trading does not require a large capital. we can start from very slightly. for example, we can trade altcoin to conserve our capital.
yes I agree unpredictable but having knowledge and experience would definitely up your chances when trading. you may lose some, but from experiences the movement of the coins will not be negative all the time