You should use cards you OWN or RENT. Starter cards don't give you rewards anymore. If only some of the cards you use are owned or rented, the rewards are reduced accordingly.
Here's an example, from Splinterlands' post:
You should use cards you OWN or RENT. Starter cards don't give you rewards anymore. If only some of the cards you use are owned or rented, the rewards are reduced accordingly.
Here's an example, from Splinterlands' post: