- prescription medicine
- dental
- vision
- mental health
- things like physiotherapy
I don't have to deal with this as we are a (very) small business but it's a major headache for larger small businesses. Basically, as an employer it simply isn't fun to be forced to be in the "providing access to healthcare" business when that's not your core business.
It is for most large employers as it helps depress salaries and reduce competition from startups. Employees will want to work for a large employer that lets them pay for health insurance with pre-tax dollars, among other tax advantaged benefits that having a well funded HR department can provide. And employees cannot easily compare compensation at other employers so they are more likely to stick around than shop around, reducing the need to increase pay to keep up with the market.
Employers can also tweak compensation by modifying deductibles/out of pocket maximums/healthcare provider networks, and most people's eyes will glaze over before they can figure out if they got an increase or decrease in their total compensation.
My US benefits were middling in terms of coverage and package when working for a large F500 and went about $16k USD on a 180k salary -- converted is about $19k CAD at todays rates. Including co-pays and fees it's like 10% of salary. At the time I was in a big city with great hospitals and doctors, but not noticeably better than Canada even at the higher price.