My OP DOES NOT have to do with any particular device or function as many have incorrectly assumed!!! It IS NOT seeking advice about 2-way audio or any other function on this or any other device. Reolink 2-way audio was given only as an EXAMPLE of a product function that doesn't work with HA but does work with the OEM app.
Please read the first sentence and take it at face value... What does "Works with Home Assistant" on the package really mean? That is, and always has been, the question. This applies to many devices that have purchased the right to display the badge.
What is the criteria to be considered "working"? Please do not link to the program sales promotion page (https://works-with.home-assistant.io). It does NOT provide any technical details and does not answer the question. "Works With Home Assistant helps clearly indicate to the large Home Assistant community which devices provide the best smart home experience, both now and in the future." Provides nothing specific.
Are the only criteria; being available, use local communication, be updateable and being end device? Nothing about functionality or useability? If all an OEM must do is meet these few criteria then the annual subscription fee appears to me to be potentially profitable. HA established the price, I doubt seriously that they chose a price that would lose money. I only bring up the fiscal end in response to Miranda's implying there is no profit. I don't care about that.
I'm curious now why the question seems to have hit such a hot button receiving such hostility and attempts to divert. It is not a difficult question to answer. What is the criteria for any device to be considered "working"?