What most forget is that this is native Z-Wave not WiFi, 433 or other communication frequencies and protocols.
If you want a development board to integrate directly without serial adaptors or plugins then this cuts other devices out of the loop.
With the WiFi spectrum becoming flooded, it's easy to forget that WiFi devices and their ilk may not function correctly, while Z-Wave on it's dedicated frequency will.
I have several projects for this in mind, one of which involves communication with a MegaA. To me that is combining the best of both worlds.
if this is a product that you are trying to sell or get a kick back from, then i understand and i'm not trying to be a hater.
but to me this is very expensive and you can accomplish the same task far cheaper. for example, i'm putting in some under cabinet lighting.
I considered a native zwave solution, using the fibario rgb device, it's $70. i purchased a node mcu for $6 and am achieving the same results.
I personally don't have any wifi reliability issues, but I recognize that is subjective to the environment. but i have dozens of wifi devices, as well as zwave, 433 and other RF devices. I really don't have any issues with them.
I would certainly prefer to have a native zwave solution. but the cost to implement vs going wifi is substantial. If you have the extra money then great.
but when you can buy 10 esp based arduino devices for the cost of 1 of these.
if the cost was much less (and i know that zwave chips are more expensive) then it would be more ideal.