yes there is no doubt about this that bitcoin is a safe investment and that is the reason that i have invested more than my 70% assets in bitcoin.
Its not complete safe hence the word itself mean 100% no risk if we intend to say safe. As we all know bitcoins price is too volatile and we wont know on what would be the price on the future even thinking on the price of tommorow because anytime it could rise or fall. 70% in your assets is somehow a crazy thing to do for me.
The bitcoin price is quite volatile at the moment. That is becasue not many people use it, it is mainly a speculation tool.