No I never think it is safe investment because knowing how bitcoin grows there is a chance of crash on anytime that make it a risky investment but we can't deny the fact that it really attracts lots of investors that makes it a good investment indeed.
There is nothing like a safe investment, except if you are investing in your skill set.
Most investments have their own risk; the only difference is the level of the risk of every investment. Bitcoin has its own risks when compared to other investments; the best thing to just be on the safe side is to invest what you can afford to lose. Even our own currency is not safe.