I don't know about other people, but when I think about a shopping list, I don't necessarily think about this requiring a specialist third-party app. My shopping list may just be a text file that I use Notes to open, and it might not be so much a traditional shopping list as a list of presents ideas to look out for, or an email from a friend, or a price comparison website, or a free-text field added to a contact or To-Do or Calendar item (if this is possible) etc. For ease of flexibility, I would rather not have to copy and paste this text into a rotateable app.