> Can someone explain to me, the difference of Morphos:Fonts and
> Morphos:MorphOS/Fonts to me?

It's the same as the difference between MorphOS: (aka SYS:) and MorphOS:MorphOS/ (aka MOSSYS:) in general, i.e. the latter contains the private OS fonts while the former is for 3rd party fonts you can install at will.