Full Idea
The basic use of the ordinal numbers is their use as ordinal adjectives, in phrases such as 'the first', 'the second' and so on.
Gist of Idea
Ordinals are mainly used adjectively, as in 'the first', 'the second'...
Source
David Bostock (Philosophy of Mathematics [2009], 9.5.iii)
Book Reference
Bostock,David: 'Philosophy of Mathematics: An Introduction' [Wiley-Blackwell 2009], p.301
A Reaction
That is because ordinals seem to attach to particulars, whereas cardinals seem to attach to groups. Then you say 'three is greater than four', it is not clear which type you are talking about.