Such a strange fascination in this thread about waxing plastics.
It is only partly to protect them in one swoop. It is also because wax/sealant products that are not made to be used on plastic, rubber, or vinyl decals can typically leave a terrible residue on them. Even if I were to decide to use a different product for them, it is nice not to have to worry about precision. Precision takes time. The less time and effort necessary, the better. My old 08 Jeep is gives physical testimony of how Ice products that can be used on plastic and rubber can easily protect and preserve the whole vehicle's appearance with one simple product, quickly and easily.
I hope that explains that it is more than fascination, but rather an issue of practicality that is important to some of us who have been a bit spoiled by previous TW products.