Personally I would not recommend any ceramic coating on the Merino leathers. The best way I have taken care of BMW Merino leather over the years is with Leatherique Rejuvenator (once a year) and Leatherique Pristine clean (every month). This is my regime and the leather in my cars look brand new even after 3 years. Leatherique is safe on BMW Merino, Aston leather and also the Rolls.
Here is a post I had on this topic.
https://www.7post.com/forums/showthread.php?p=22959753
Before and after on my G12 seats.
https://www.7post.com/forums/showthread.php?p=23301916