I’m not a fan of insurance companies, but the dental/medical insurance split makes sense. Insurance is fundamentally a risk hedging game. It matters what the risks are. Most medical conditions will only happen to a small percentage of people, so we can all put money into a pool and pay out to the unlucky people who, for example, get cancer. Almost everyone needs some dental work eventually, everyone’s teeth wear down. Dental insurance is more like a savings plan than a gamble on rare outcomes. It doesn’t make sense to pool those risks together.