There are times when it would be nice to force the timestamp to be
updated even when the data stays the same. For example, if an address
was entered into a database 10 years ago, it's nice to have an easy
way to tell the database "yeah, that person still lives there, so the
data isn't 10 years old, it's current".
Of course, with proper design, you can have a nice facility for this.
But not everything is well designed. We still have to tell folks from
time to time that they have to make an inconsequential change to an
address (like change 'ST' to 'STREET' or 'ST.') in order to update it.
Or to confirm that some company still has 5 lawyers, first change it
to something else, save, then change it back to 5, and save again.
It's utterly embarrassing.