Segwit is not only for lower transaction fees.
It fixed transaction malleability and enabled HTLC's (was necessary for implementations like the LN).
Thats not true.
Hardware and paper wallets are way safer than desktop wallets itself.
Wether electrum is safer than other desktop wallets can also not be said for sure.
Every transaction has to be signed with private key.
This is not a feature tied to electrum...
bech32 is not an 'additional version'. It is like a 'default' segwit, or 'native' segwit.
Nested P2SH (segwit addresses starting with 3.. ) are made for transition from legacy to segwit and for full backwards compatibility.
There is a mobile version of electrum.
While i think there are better mobile wallets, it is still a considerable option to choose from.