Isn't plastic supposed to be bad?

Normally, yes. We tend to stick with materials like titanium, copper, and bronze because of their toughness and corrosion resistance. Ultem, however has high mechanical strength and heat resistance which makes it ideal for harsh environments. Natural and Black are easy to find but additional colors is rare. Thankfully, we were finally able to get our hands on a special run of opaque Green and Blue from a mill that had a small batch left over.