Embeddable in-metal RFID

I am new to RFID but relatively familiar with how it works and its limitations. However, I recently learned of an advancement in the tech known as embedded in-metal RFID, which appears to be a newer evolution in the tech and a product offered by very few suppliers thus far. I believe this type of RFID may address a problem I've been trying to solve for some time - unfortunately there seems to be very little information available on the web.

So can anyone here explain this evolution in RFID tech to me? How exactly do these readers/tags penetrate metal? Is there a limit to the thickness of the metal material the tag or reader is embedded in? What are the drawbacks of this type of system vs the standard LF/HF systems that cannot send/receive signals through metal?