i don't really think using bitcoin as a retirement account is the best option because the future of bitcoin is not certain as nobody really the future. Predictions is possible but it is not 100%. It could be profitable at the longrun or not profitable at all. Well, everything has risk, you just have to gauge the risk very well before taking the decision.
Nothing is sure with related to investment at present Either you go for gold or real estate no one guarantees you the profits but you can trust bitcoin over the gold or land as the financial gurus have predicted that it is the future currency but you need to follow your heart and your mind to get into a particular decision.