When I first heard of Cryptocurrency my friends told me my money would be more secure in crypto than the traditional banks and that I would be my own banker. So I opened a wallet only to hear that some person’s accounts were hacked.
Your words are correct, if the security means that your money will remain in your account, but you will go to another place, and it is something that exists in banks in general, especially with the presence of parties that insure deposits of depositors up to 250k USD, but if you are from a troubled country such as Lebanon, in which even depositors cannot withdraw their money From banks, then Bitcoin is the best option.
In terms of value, the price of Bitcoin, according to historical data, is on the rise in the long term, while all fiat money is declining.
According to MIT Technology Review, less popular blockchains have fewer nodes, making it easier for hackers to launch 51% of attacks. In 2018, hackers attacked a relatively new cryptocurrency network with a small number of nodes. You can read the MIT Technology Review report to know more. Some coins like Monacoin and Bitcoin Gold fell victim to these 51% attacks.
Even if 51% attacks occur, your old coins, for example, that you bought the day before the 51% attacks occurred, are not at risk, but all new coins, meaning that this attack forces you not to send coins until it ends, but it has no effect on your old coins.