no you assumed wrong. electron cash may have malware in it and that is why the recommendation is to use a separate computer. when you install malware on your computer it takes over the entire pc. Doesn't matter which electrum wallet you have your coins in. if that new wallet is on the same pc then it can be affected by the malware too. that's why they recommend you install it on a separate machine or a isolate it in a virtual machine.
Isn't that only an issue for for M$ Windows machines when installing a binary? I have seen a couple of discussion about that, but the recommendation in that case was to install from source, which is what I did. Not saying that this may be safer, but what else to do if no second machine available and no VM setup in place (and I really did not want to fiddle around with that just for one app)?
Of course I can hold off using Electron Cash for now, I'm in no hurry to transfer or sell my BCC, but in the end I really would like to have a wallet for BTC and BCC on the same machine just for simplicity.