For example, Facebook is starting to let people use Instagram to send a photo to someone using Messenger, and vice versa. In the future, you might be able to text a friend who uses only WhatsApp, which Facebook also owns, from your Messenger account.
There might be — possibly? — handy things as a result of stitching these apps together, particularly for businesses. But the more Facebook operates as a unified empire and not a constellation of apps, the harder it becomes for a government to break up Facebook and the tougher it might become for rivals to chip away at the company’s dominance.