So you want to call it "savings" if you keep Bitcoin? Fiat money isn't an investment because it continuously loses value. Bitcoin, although designed to be peer-to-peer electronic cash, is mostly used as an investment nowadays.
I wouldn't recommend to keep all your money in fiat either.
The bold part was my point but yes these days bitcoin became an investment, the reason I think was posted in my last response. The industrialization of mining, add holding nature of the users with it. Real estate, gold and silver are still safe and secure if anyone consider investment.
Bitcoin is volatile, the price moves against what? 1 sat = 1 sat.
I used to say "1 BTC = 1 BTC", until I realized that's like saying "1 USD = 1 USD", and it's not true. That's why USD-prices are usually related to a year: a dollar in 1960 was worth a lot more than a dollar now. And a Bitcoin in 2010 was worth a lot less than a Bitcoin now.
True, it make sense. The comparison seems to be the value needs to be determined by value received from the current economy compared to the value received in a given period of time in the past.