I agree with you that crypto systems have such good security that they are almost unhackable. The main enemy of crypto is phishing and malicious malware that will let someone know your keys. And when the key is known, all assets will be lost, without notification that your assets have been sent to someone else's wallet

Whereas usually things like this can still happen to both beginners and those who already have experience. We must always keep a copy of the key and don't get into phishing sites so that the assets we have are safe. Crypto is a digital technology and in the digital world nothing is 100% secure. When hackers cannot attack crypto networks, they will attack asset owners to find out their wallet keys.

If you want to hold bitcoins for a long time, I suggest you buy a hardware wallet, and never keep bitcoins for a long time on a centralized exchange.