> * You only need one binary to work with TeX. Either PDFTeX or LuaTeX. All other binaries are just glue code (for example to generate missing Metafont fonts, but who wants them these days anyway?
A lot of TeX uses Computer Modern to typeset the body (a metafont font) and I don't think I have ever see a TeX document that doesn't use Computer Modern or Euler (another metafont font) for equation typesetting.
I also wonder whether it's possible to achieve the excellent equation typesetting capabilities of TeX without metafont.