I saw this in the release notes for today (under zwave accordion) and now see these ‘lights’ but don’t understand what they are. They appear to have dimmer functionality through the UI but my lights aren’t dimmers. What’s is the purpose of these controls?
I checked the Zwave doc but didn’t find an explanation there.
Your question confuses me. Quote the “Release Notes” because there are release notes almost daily for different integrations and components.
The light integration has dimming options because the same integration can be used whether the physical light is dimmable or not. If your light is not dimmable, ignore that option.
If these are GE/Jasco switches that are affected, you can ignore the basic entities. The entities will be removed (unavailable) when you upgrade Z-Wave JS to v12.3.0 as they are not supposed to exist. Currently none of the add-ons or applications are updated to that version yet.
Thanks! Yes, these are all GE/Jasco devices.
Can’t read my mind? 
This is the part from the release notes from today:
Basic Command Class values were previously exposed as number entities and were disabled by default. They are now exposed as light entities and are enabled by default.
If you have scripts or automations that use any of these number entities, they should be updated to use the new light entities instead. Any previously created number entities for this Command Class can safely be deleted once you have validated that your scripts and automations are up to date
To expand on the release notes and your original question (“What’s is the purpose of these controls?”), the Basic light entities are only created when the device does not support any other actuator Command Class, such as Binary Switch (toggle switch) and Multilevel Switch (dimmer) CCs. It’s a Z-Wave certification requirement to support controlling the devices this way.
There was a bug pre-v12.3.0 that causes these light entities to be created incorrectly for for GE/Jasco switches, because they have a special configuration to support double tap events (which are Basic Set commands).