If you cant get celebi without a cheat, what is the point of the shrine in ilex, is it useless?(heartgold)
My answer is the same as DT's, with one change. It is also where you meet Spiky-eared Pichu.
There is no use for the ilex shrine if you don't have celebi, but with celebi it takes you 3 years in the past, you learn that Giovanni is your rivals father, and you battle giovanni.