As a Solutions Partner, I had a client purchase CMS Hub Starter (it's a one-person startup consulting business). We knew themes were included in starter and the 15-page limit wasn't going to be a problem. We just wanted to build a basic infrastructure in HubSpot from the start that could grow and scale over time.
But the theme we wanted to use wasn't available to us, because it requires CTAs (and we don't have CTAs because we don't have a CMS Pro or Marketing Pro license). As an experienced HubSpot partner and user, obviously I understand why this is the case. But this was not communicated to us beforehand.
Currently, there is no way to see which themes will or won't be available for users with specific licenses until after a license is purchased (when the "Buy Now" button is grayed out). It would be supremely helpful to be able to filter themes on the asset marketplace by which HubSpot licenses (Free, Starter, Pro, etc.) they are compatible with.
I predict with the launch of CMS Starter and the growing number of themes on the marketplace, this will continue to cause some confusion and frustration for both partners and customers.