What I'm looking for is reasons I can give my company for why they should contribute to their employees' HSA accounts. They already offer HSAs and high deductible health plans, but they don't contribute any to the HSA. I'd like to convince them they should contribute. Would there be any advantage to contributing to the HSA over giving raises? Maybe having to do with payroll taxes or something?
Some companies tend to subsidize their health plans pretty heavily. Suppose the fancy non-HDHP health plan has a true cost of $1,000/month, but you charge the employees only $200. The employer subsidy is then $800. Suppose the HDHP has a true cost of $600. That's a lot less! Even if you don't charge the employees anything to be on that plan, you're still subsidizing them 25% less than if they were on the fancy plan.
An HSA contribution is a way to essentially set the HDHP premium to a negative value, more of an incentive for people to switch off the fancy plan and on to the HDHP. These contributions raise the subsidy for the HDHP, but if it's still lower than the subsidy for the fancy plan it can be a win-win.
I don't think there's much difference tax-wise between a direct employer contribution to the HSA compared to a salary increase that the employee then puts in the HSA. A salary increase that the employee chooses to keep out of a tax shelter would be taxed more.