The thing is... Electrum comes pre-installed with Tails, but it is not the latest version. So if you update Tails on a "Persistent Volume" to the latest version of Electrum, then you effectively void the benefit of having a clean boot every time you use that "Persistent Volume"?
To keep the private keys offline, it doesn't matter if you update Electrum before entering your seed phrase. But you'll have to make absolutely sure the system stays offline until you turn it off. A physical network cable is obvious, Wifi needs more attention. Note that creating seed words on a system that has been online could mean the seed is compromised already.
You probably don't have to update Electrum each time: a slightly different version number is okay for signing transactions.
I have swept many coins from Paper wallets to Electrum without any problems..... but I guess I have just been lucky.
Think of it as
seed seat belts: I've used them many times, but never needed them. But I keep using them, for the one time they'll save me.
I am still looking for a program that can encrypt a "Private Key" offline and then when it goes online.... that program decrypt it and sweep the keys.
How about
BIP38 encryption? Bitaddress encrypt and decrypt this (offline). No need to sweep the funds online, you can still sign offline.
If you use this, make sure to test recovering your private key
before funding your address!
After I sweep a key... I quickly transfer the coins to another Bitcoin address.... because I am just paranoid.
If there's malware, you'll be too late.