Seeing as it doesn't really affect the Creatchi itself if left alone, I don't see much point to it.
In the Tamagotchis and cyber-pets that Creatchi aims to emulate, the idea was usually that unattended poop would eventually make the pet sick, so it was in the players' best interests to get rid of it as soon as possible. If the Creatchi poop behaved the same way - ie. made the Creatchi sick - or had some other detrimental effect, then there would be more incentive to clear it.
That's just my view, anyway.