Links tend to be updated.
If I link to a Wikipedia page, it will get updated.
On the other hand, if I am writing a WhatsApp message to another person, they have no news source, they can’t check anything.
Also, a picture. They can’t check anything.
If you give a link, you can check a lot of things.
In programming, you create a function that does a simple thing – you feed that function some variables, and the function returns a value.
By using functions, you can focus only on updating parts of the code.