I am technologically knowledged to set up both an offline wallet and an watch-only wallet.
But If I get robbed, someone steals the offline computer and discover my electrum password I am dead right ?
If you plan to HODL, i.e. won't actually spend the coins, you can write down and save safely in multiple places the recovery seed, keep the watch only wallet and wipe the offline computer (or use a live OS from start for the cold storage).
If you indeed want to spend and use the cold storage then you have options like:
* use an OS with strongly encrypted HDD
* use live OS with no persistence (just then you'll have to access often the seed, hence sub-optimal)
* use a strong password for your wallet and make sure you can move the coins to safety in a timely manner after the cold storage theft is noticed (using the seed backup)
So if you use a hard-to-discover long password (or phrase) you're not "dead", even in case of theft.
LE:
Also keep in mind that the "offline computer" can actually be an-OS-on-an-USB stick, which can be hidden easier and doesn't look that valuable as a laptop.