Wet Diamond All Metal Sealant is has a much higher concentration of acrylic polymers, you could almost consider it an acrylic sealant (although it still has the other blended Wet Diamond Polymers).
It is more temperature resistant than Wet Diamond All Finish Paint Protection BUT either product is extremely stable in extremely high temperatures. Metal Sealant is designed, as the name implies, to bond primarily to metal surfaces. Many customers of BLACKFIRE have used it on wheels (painted or metal) with great success as well.
In terms of looks, Metal Sealant (like most acrylics) is going to be extremely shiny and glossy which looks great on the silver painted wheels, chrome, aluminum, and other metals. You could apply it to paint (it won't harm it) but it will not last as long (on paint) as AFPP.