No, I think, it's definitely not, the  price of bitcoin quite volatile.One can gain or loss a huge amount in a very short period.So if we're talking about an asset that offers a stable rate of return, Bitcoin ain't it.

Also, It can be hacked or stolen, so, don't put all of your money in bitcoin or any other crypto currencies.On January 18th, 2016 hackers stolen $6 million USD, equal to 13,00 BTC and 300,000 LTC from Cryptsy’s safe. The hackers inserted a Trojan malware into Cryptsy’s code so that they could access precious information and transfer cyber currencies. Cryptsy is under investigation by a US federal court as it held “hostage” money belonging to its clients. The account holders were in fact denied access or unable to withdraw funds.

So, Bitcoin isn't, definitely not to be treated as a safe.