I wouldn't say that it's the safest investment available in the short term, but I think that it's probably one of the most viable long term store of values that are currently being undervalued.
If you look at the characteristics of bitcoin, you actually see a lot of resemblance with another safe haven asset class which has been recognised traditionally, which is precious metals, especially in gold and silver which has been used as currency for centuries.
The defining aspects that make both precious metals and bitcoin good long term store of values, and thus I guess "safe investments" would be the fact that it is decentralised in terms of its supply as well as the hard limit on the supply.
Bitcoin holds an edge in terms of the actual profitability in the long run compared to gold, which has already been used for centuries, though. Since bitcoin's demand is still climbing as adoption grows, and there is still the same limit on the amount of coins that are able to be in circulation within the supply, it's honestly simple economics that bitcoin would be at the very least, an effective hedge against the inflation that takes away value from fiat currencies daily.