What they said ^^^. I’m struggling to think of a good reason why you wouldn’t want contents insurance considering the marginal cost. Most people don’t realise just how much all their ‘stuff’ adds up and would cost to replace should it go up in smoke. Unless you really can fit all your stuff in a bag and replace it for few hundred quid then just get it.
After much arsing around with M&S a couple of years ago (see those other threads) I’ve now got building and contents for less than half of what I was paying with M&S including all the bikes as specified items. Sainsbury’s insurance btw.