Even with Tor, you still leak all your addresses and allow them to be linked together. The only way to be anonymous with any Electrum wallet, watch only or not, is to connect it to your own node/server.
You leak your wallet addresses but tor will mask the IP address in a way the central server will not know the IP address. To have a full node wallet needs over 400 gigibyte and addictional gigabytes daily, that makes people not to have full node wallets. The only way to complete privacy is to have your own electrum server or full node and connect to it instead of the central servers, but not everyone that can afford this.
But that is if you can get Electrum to connect through Tor in the first place. As far as I know, Electrum makes direct connections to the servers, which I believe are unencrypted on top of that, and also it does not have an option in the GUI to use a proxy to connect to the servers. And certainly not a SOCKS5 proxy option.
With ANdroid you can use things like Orbot to route apps' traffic through Tor, but as for the desktop wallet, I am not quite sure.