If you want a retirement fund or if you want to secure your future then buying bitcoin or collecting it while you can is the best option for you to have a secured financial future state. Most of the people are putting their bank account savings in bitcoin because they believe that bitcoin has more potential than the interest which is very low in banks.
So far bitcoin seams like good option for that. And i also think that it would be a god idea to leave some amount of bitcoins for future. If we look back in future, bitcoin was only going up. Price started at some really little amount, and look it now, its almost 3000 dollars per one bitcoin. So who knows maybe in future, when it is time for my retirement bitcoin will be worth 300000 dollars 
, or maybe it will be nothing.