In DT1987, she didn't appear, because she's ultimately Donald's girlfriend, and since Donald almost never appeared at all in the early seasons, there was no incentive to ever show her at all. Other minor duck family members like Gladstone also only ever appeared once, and then nevermore.
As for the 2017 version, the head writers don't know how to really include her yet, and for now, the show's busy having a crap ton of characters anyway while setting up the Della mystery and recovery arc.
Perhaps Daisy will appear for season 3. But definitely not yet for season 2.