Yes, Bitcoins are new era of getting money without any single cent investment. i left my job also i spending my job timings in bitcoins only.
Bitcoins are very usefull who are unemployee/ whose salry have not sufficent. No doubt they can invest on Bitcoins.
Btc is definitely a good source of income but you are pretty sure of the stability of this source of income when you quit your current job and justify your time for btc. I am very concerned about this as btc is still in a lot of turmoil and first August is sure to make some changes.