Long before Health Insurance was an employee benefit there were credit unions offered by employers. Some might even say the credit union was the original employee benefit. Credit unions still try to market through employers, doing lunch and learns, etc.
A credit union HSA account offering is a great way for a credit union to get employers to sponsor the credit union for its employees. More exciting about the opportunity is it almost certainly guarantees new members. So if your a credit union trying the employer strategy or not ... offer HSA accounts, it's a no brainer!