I feel like gift shiny prizes should always be accompanied by the choice of a lower-tier tradeable shiny, like in that other tournament that I can't quite recall.
Shellder is neat though, even given the option I'd probably still choose gift shellder, I just feel in most cases people would prefer a choice.
EDIT: Never mind, the options never include either a gift or non-gift shiny, but either way i feel like it should.