Once you have shared your content to the world, it is accessible for anyone to use it.
For example, other AGOL users (whether from your own organisation or anywhere in the world) may choose to add your feature layers to a web map. Then, if you change or delete this data, you could inadvertently break someone else's content - in fact I have done just that very recently.
It would be extremely useful if on the item page there was a tab "used in" that lists where that item is being consumed, giving the opportunity to contact the content owners and warn them about up-coming changes.