What's insecure about it? Heard of a lot of cases where money were stolen from people banks accounts/cards using scamming, viruses etc (and witnessed one right when it was happening), never heard of problems because of card being contactless. It also lets you not to flash your pin in front of the whole store for many of the payments. I think on the convenience/security scale it's very high.
They limit it to low value transactions specifically because it's not as secure. Feel free to dig into it if you don't trust the industry's assessment.
They limit it to make it secure and make it pointless for the thieves to try exploit it, at the same time covering many quick payment needs - convinience/security balance I mentioned and you ignored. And feel free to think about industry's assessment - they make more and more cards with contactless payment capabilities and it's used very extensively in some countries of the world already.
to make it secure Security is not binary. It's trusted less than physical contact readers for large value transactions for very good reasons. They care less about low value transactions, but that's not a security question.
You may not care about security, but all I said was it's worse, and not good enough for me which you have not denied.