It's silly to charge $40/mo per use to use model driven apps, but only allow the CDS data source. Well, it's silly to charge $40 regardless. If I have 1,000 users my spend would be $40,000 per month. $480,000 per year.
That's insane, and I believe the sample app 'New Hire On Boarding' was created in bad faith. If I wanted to deploy something similar would mean every single domain user would require a subscription.
I believe $40/month for designer licenses, and something much more reasonable for standard users would be the way to go. As is, the current pricing structure makes this an impossible sell to the enterprise.