Do you think this topic is valid or is it a lot of unnecessary paranoia?
Well, I really dont know about that but it seems you are making us aware of clipboard virus or Trojans and I know very well that most people on this forum are ware of such so what then are you trying to relate through this thread?.
As a Bitcoiner, the security of your funds should be your max priority since you don't depend on third parties on storing them.for long these clipboard virus, malwares, Trojans have been a thing in the crypto space and so many investors had lost their funds to such. Once they find a way into your device, you might not be aware since these scammers designs them in a way to remain completely under detectable for a normal person who knows nothing about them or his security.
They are designed to steal your password, monitor your transactions and your activities unknownly and gradually they key into your personal life until they finally get you reaped.
Agree that, instead of using the mnemonic as a backup, a simple backup of the wallet file like Bitcoin Core, Electrum, Bitcoin Wallet for Android do, does not reduce remote access to your wallet much more, since in these wallets we have to encrypt and then export them to external drive?
Well, it how depends on how well you store either of them. storing wallet files encrypted on an external drive provides a layer of security, but it may still be susceptible to potential risks such as drive failure, loss, or unauthorized access if the encryption passphrase is compromised. Mnemonic phrases, if stored securely, offer a more resilient and versatile backup solution for cryptocurrency wallets. But just as I said before, the security of your seed phrase or wallet dat files purely depend on how well your store either of them.