Night vision and Thermal are very different technologies. You can think of night vision as a super-power that allows you to see, just like your natural eye, but in very dark conditions. All night vision needs a little bit of ambient light to work, for example the moon or some starlight.
Additionally, the SiOnyx night vision is full color and our Pro version will operate in "moonless starlight" conditions which is similar to a Gen 2 tactical night vision optics that the military uses.
Thermal picks up on "heat signatures", not visible light. The benefits of thermal is that you don't need any ambient light and you can see in the pitch black as it's not looking for visible light, and only reading heat signatures.
Powerful enough thermal can also punch through fog, again because it's not looking for visible light, and only reading heat signatures. Thermal technology has a come a long way and the more expensive thermal optics ($40,000+) is very impressive, however, the lower end thermal optics (sub $15,000) has limited functionality.