I agree with Bob, there is not a single scenario, including one with many children, and lots of medical needs, where an HSA is not the best way to go, from the perspective of strict fiscal economics. There are emotional and practical situations where it may not be wise to pitch it, but as a general rule, everyone would benefit from it.
If you can do a good job of truly explaining it, then most of people will realize the folly of paying extra premiums for an expensive co-pay plan.
On the other had, if you are trying to explain the concept, and you just KNOW that they are not getting it, it may not be the right time for them, they may not be ready at this time.
Write them on something that they want....
And keep educating them.
I just put a client I've been talking to about HSA's for the past two years who I put on a Co-Pay plan 3 years ago.......now they see the value of the HSA when they see all the premuim $$ they wasted for the past 2 years, almost over $6,000.
And they could have had the same quality plan for half the cost...and been $6,000 richer.
Be an advisor to your clients doesn't always mean they will do what YOU want them to do, it means showing them what you believe is the best thing for them to do.