How to upgrade from packing tag to Sprite Atlas

Currently, our project uses the packing tag system. I would like to upgrade us to the Sprite Atlas system as it will improve our workflow.

Are packing tags and Sprite Atlases mutually exclusive? Are there any good strategies for upgrading to Sprite Atlases?

We are currently working in Unity 2018.4.23f1. I suspect an upgrade to Unity 2019 in a few months.