Well, it doesn't really add any feature that might affect the gameplay or an aspect of it in any way, hence "do fuck all" but sure, it can prove convenient to those whom you referred to. Problem would be integrating old shiny encounters, which is probably impossible (not sure) so the very feature's effect might have to start-off when its implemented.
On a side note, i'd like to suggest a minor upgrade to this topic, which is to add total shinies owned of the said shiny globally (example ; there are currently x number of shiny rattata's owned) that way, it might also help values settle down within the shiny market as well