“Bad deal” in this case is purely from a mathematics point of view.
For example, you have camera equipment worth $2000 and there’s a 10 percent chance something happens and you make a successful claim with the insurance in the next ten years. So on average, you get 10% of $2000 (=$200) from the insurance within 10 years. Per year, that makes $20. If you’re paying more than $20 a year, you’re spending more than you can expect to get back - on average.
Obviously, those are arbitrary numbers and they could be way off. But the insurance company will do the maths right to make sure they earn more than they spend. And it’s in their best interest to avoid customers who are likely to cost them more than they receive.
Of course there are cases where making a bad deal in a mathematical sense can still be beneficial overall. Your car loan is a good example, health insurance is another. And if photography really is the only thing that brings you joy, then you can accept a “bad deal” to make sure you can keep pursuing you hobby,
But an insurance is never a good way to save money. On a case-by-case basis, it can be, but on average, it isn’t. It’s like playing in a casino, you can leave with more money than you had before, but on average, the bank always wins (unless you’re cheating).
Insurance companies are very good at taking more money from you than they give back. The ones who don’t aren’t around anymore.