On average one loses by insurance, else the firms would go out of business.
Also just because it is stolen, lost or destroyed, does not mean you will get paid it's value.
There are a lot of very hard nosed people at insurers who's only work is to stop people getting paid.
Even if you don't fall foul of their many exclusion clauses, they may well still just say "you must have left the window open", or something, and put the onus upon you to prove it.
Thus you should only insure in one of two cases.
You know that the insurer has miscalculated the risk. This does happen, but they do this for a living so it's not a good bet usually.
The loss would be catastrophic, such as your house burning down which you could not afford to rebuild out of your cash flow.
If our electronics were stolen, then I'd be annoyed, but we'd just buy new ones, which will of course be better. No one is going to steal my clothes (trust me on this), yet the replacement value of most people's clothes is more than their electronics.
Also you will have a big fight with the insurer about producing receipts, and of course they try to pay the "value" of the goods stolen, which is only a fraction of replacement.
Insuring paintings etc is just buying trouble. People who trade art for a living find it very hard to get prices right. The insurer won't say "ooh a genuince Connor, must have doubled what you paid for it".
Also the margins on art are a lot more than other things you buy. Mark ups of 50% aren't exactly rare. Thus the price you could sell the picture for is a lot less than what you would have to pay to get it. Guess which the insurer will offer ?
Thery may also claim that you took the pciture away and sold it yourself. How do you prove that negative ?