Well, for one thing, that’s what photographers do. Sounds trivial, but there you are. You see something, you take a picture. Quite often of stuff that no one who isn’t a photographer would take a picture of. I guess it’s a mixture of reflex and trained eye. Sure, a lot of it turns out to be crap, but every once in a while you strike gold.
And in a setting like the White House, you’ll rarely know in advance whether the next day will be “same old, same old” or “historic event”; sometimes that distinction will be made much, much later. So better take a few pictures more, just in case.
This is an excellent idea. Not just for El Presidente.