It's fun. :-)
My cats have full names - first, middle, last - and it's just for fun.
Although, like earthnut, they have lots of odd names.
Jasper is Jazz, Jazzy, Jazzbutt and Jazzaroo (the vet called him Jaspy which annoyed me to no end.) Zeta is Z, ZZ Top,
Zed.
Pluto is P, Mister P, P Fluffy Jones and the boring Plut. MacDuff is
Duff, Duffers,
Duff, Duffleupagus and
Laird MacDuff.