I installed Electrum and created a wallet there. All I know is the seed generated. I don't know private keys from the Bitcoin addresses it manages for me. And I don't see an option to get them from there. So, the question is how safe this system is? Won't I lose my bitcoins one day?
Electrum is a wallet software and this provides more security than online wallet. Although it's not the safest wallet, compared to hardware wallet. But it is safe because electrum has lots of extra security features. Such as seed phrase, the encrypted wallet file containing private key is protected with a password and also two-factor authentication. This also adds extra security to the wallet.