You’ve probably heard this “not your keys, not your coins“.
Indeed, as long as you’re not the sole custodian of your private keys, your cryptocurrencies probably don’t belong to you.
When you leave your cryptocurrencies on an exchange platform, you’re delegating your wealth to that platform. It can, at any time and arbitrarily, cut off access to your account, depriving you of your assets. When you use a hot wallet, such as a web extension, your private keys are stored on your computer. They are therefore vulnerable to Internet threats.
So yes, if you value your cryptocurrencies, use a hardware wallet to store your private keys offline, in dedicated equipment.