It has been said that there is no Mediawiki need for text colourization or highlighting.
For uses outside of traditional Mediawiki use this may not be true. In a similar way that underlining, line through or bolding adds meaning to a text, so can the addition of colour.
For example. I live on very complex searchable ToDo lists. For years, I used a bar of highlighter colour on the paper version to indicate action, urgency and status. Its is far faster and much more accurate to scan a large document for a colour than to read a descriptive text.
That was when I used paper. The use of colour on paper is in some ways superior to a computer screen.
Mediawiki used as a newspaper or library book for text retrieval only may have no need for text colour and highlighting. But I suspect, there are many who would find it extraordinarily useful.