There are trade-offs. My folks share an Apple ID too because of photos and being able to keep all photos on their devices easily. Of course, that means a lot of other things are automatically shared too. And, some services that are meant for individuals (FindMy, etc.) don't function as intended. For them, it's worth it because they don't have to figure out the tech or remember to share photos to have all the grandchildren's pictures/videos in one place.
Long story short, not everything will function as intended is they share an Apple ID.