to me the best option is to invest your money in bitcon, and there you can get double services, one is that your money will be too safe in bitcoin and the second is that you can really make a good profit just for holding your bitcoin, therefore the best option is to invest your money in bitcoin.
Investing in bitcoin is not safe and involves huge risk as we don't know where bitcoin will land in future and what price it would be holding so you should invest only that you can afford to loose.
But the same can be said about almost anything, if you are holding fiat, guess what? You are invested in fiat and the government backing that fiat money if for some reason that government failed the same will happen to your fiat.