I want to know what is different between using electrum and hosting a full node (that requires bandwith and a lot of stroage)?
The difference between running a full-node and using an SPV client like Electrum is that with your own node, you check and verify the entire history of transactions from the beginning of Bitcoin. With a full node, you are just trusting someone else and you aren't doing the verification on your end.
Electrum servers can be operated by malicious parties who can find out things about you to de-anonymize you. By connecting to them, they will know the balance of all your addresses connected to that wallet, including the unused ones. They will also know your IP address and the version of your client. With a full-node, you aren't leaking that info because you are running that server.
Thank you Pmalek I think I got the answer now!
Pmalek has already pointed out the differences, if you run the full node, you will not depend on any third party, even mempool and transaction history in details are all within your reach without depending on any their party while runing full node. If you want to have privacy, you need to run full node.
More problems with paper wallets, is that if we want to transfer user funds to the main wallet, We'll pay a lot of fees to move each funds from each wallet to the main wallet.
If this is the case, it will be good to buy a reputed hardware wallet. What I think you are concerned more about is security and safety of your coins, you can buy reputed hardware walllet, it still make transactions easier.
since it's not needed for personal usage, so hardware wallet won't benefit in my case (wallet for merchant system).
