Agree with you, renting houses would be a very good investment for long term and stable profits. It would really be a good choice but the question is can we buy a house with bitcoin? If yes, then its good. The next question is do we have an enough bitcoin to buy a house? If yes , then theres no problem at all.
If you have a choice to buy the house with bitcoin or renting a house, it is better to keep the bitcoin and rent.
Yeah over part few years you would have faired much better holding bitcoin, personally i think that will be the case for the next 2-3 years also. According to martin armstrong we hit the peak in 2008 for housing prices. Bitcoin is years away from a peak if it even has a peak.