That said, at £20 a month it’s pocket money, you won’t miss it and it’s best to have it for peace of mind.
MN at its finest. It might be back-of-the-sofa cash for you, but it's a lot of money for plenty of us, including the OP, by the sounds of it. I've really needed something for 6 months that costs £18 and am only just now in the position to be able to finally get it.
If you can afford the cover and you want to buy it, it obviously brings a lot of peace of mind. As with most insurances, cost/premiums and exclusions tend to put it out of the reach of those who are most likely to actually need it. I think it can be a bit like pensions in that people will tell you to prioritise it as an absolute essential, regardless of how much it costs. If it's that or luxuries, they're probably right; but if it's that or being able to live, eat and not get into arrears with your bills now, sad and risky as it is, then the insurance/pension becomes the unaffordable luxury.
It's not an option for me anyway, as my health is too far gone for anybody to be willing to insure me for CIC. As for life insurance, I could probably get it through a specialist broker at a vast cost (maybe £200-£300 a month), but even if I had that kind of money, I have an existing condition that could be claimed to be linked to (or to have exacerbated) absolutely anything that I may die of, unless I get run over by a bus, so I'm in no doubt whatsoever that my family would never see any payout anyway.
However much insurers promote their cover as valuable peace of mind to keep you and your family protected (which it certainly can be), it's just a financial gamble on their part. They're happy to urge you as to how essential the peace of mind is if they think there's a good chance you won't be a burden to them, but if you start to look like a bad bet to them, suddenly that same peace of mind is strangely not essential at all - or even a possibility.