Why is Bitcoin not as good as money?

I've heard a lot about Bitcoin, but I'm still not sure why it's not as good as regular money. Can you explain?" "I mean, it seems like it has a lot of volatility. One day it's worth a lot, the next day it's worth less. How can people use it as a reliable store of value or medium of exchange?" "Also, I've heard about all these problems with Bitcoin transactions being slow and expensive. How can it possibly replace traditional payment systems that are much faster and cheaper?" "Lastly, I'm worried about the security of Bitcoin. I've heard about people losing their coins because they didn't keep their private keys safe. How can we trust this technology if it's so easy to lose money?" "I'm just curious why, despite all the hype surrounding Bitcoin, it hasn't really taken off as a widely-used form of money. Can you help me understand these issues?