The ideal option, as mentioned above, is diversification - part of the money in fiat for stability, part in bitcoin or other assets for growth.
If you want reliability and stability, choose fiat. Keep the money in a bank, perhaps some in a foreign currency (depending on which country you are from) to protect yourself from inflation.
If you are willing to take risks and want to try to make money on the growth of cryptocurrencies, you can allocate a small portion of your savings to bitcoin. But do not invest all your money there, especially if you are not prepared for possible losses.