Circular Packaging vs. Sustainable Packaging

The term "Sustainable Packaging" confuses me.
.
"Circular Packaging " makes much more sense.

#circularpackaging describes packaging that is designed with the intent of being collected, post consumer, and processed back into a similar packaging product. A full cycle. Packaging that is diverted out of a landfill.

Packaging that has recycled content and ends up in the landfill is still part of the problem. It is often called "sustainable".

As the Recycling Partnership states, “it helps to mitigate the question, is it recyclable or not”.
Is it sustainable? It's surely not circular.