Why does Obama need a teleprompter, or written notes, if he's repeating the same speeches?

From the Washington Examiner:

President Obama spoke to supporters in Florida this afternoon, but was careful to stick to his script, relying heavily on his teleprompters.

The president campaigned without teleprompters last month, when he made his controversial "you didn't build that" remark about business owners.

A campaign aide explained last week that Obama's slip up wouldn't change the campaign's teleprompter strategy.

“The attempts by the Romney campaign to make this into their rallying cry haven’t changed anything,” said a senior campaign official to the Hill, adding that Obama “has done events without a teleprompter since then.”

The Hill noted in mid July that, at recent campaign events, "Obama spoke to crowds... without his teleprompter, instead using written notes."

The Hill added that, "Team Obama thinks the switch, or partial switch — the president is not giving up the teleprompter entirely — will help him better connect with voters."

It is mindboggling, though, that Obama would even need a teleprompter, or written notes for that matter, while speaking at campaign events - since every speech is nearly identical, almost word for word.

Every 2 or 3 weeks, the President makes some changes to his speeches, but during a 2 or 3 week span - where he typically speaks at a couple of campaign events a day - he repeats the same exact themes, anecdotes, barbs etc., almost word for word.

Why in the world does he need a teleprompter, or written notes?