In fact you are wrong.
i didn't get which part of my comment was wrong, can you please explain?
He can restore anytime the electrum he used at the beginning by just having the seed of the electrum wallet with him every time he uses Tails.
that is right but why not just simply use a normal linux distro with normal persistence ?
What he wants to achieve of course is fully anonymity of his bitcoin transactions. Bitcoin is pseudo-anonymous by default but with this little trick it can become completely anonymous.
you don't reach anonymity by using TOR with bitcoin. bitcoin transactions (to my knowledge) don't store or reveal your IP address to the world. (what you see on blockchain.info is different)
bitcoin transactions can still be traced by chain analysis and if the bitcoin address is linked to the person then he and all his transactions can be found.