Very much true facts, for mining lot of investment is needed and more over you have to first calculate that how much expenses you will get and what will be the output, after calculating all this you will know that whether it is profitable or not. for Mining main is electricity expense which if is low then next comes investing for mining rigs. So their are lot of steps to start mining. But for trading you can start with small investment and do trading in high volume coins and gain experience and when you are fully expert in trading then you can do what ever investment in trading as per your conditions.