Duet is how to use the iPad mini as a touchscreen controller for PowerPoint & Keynote Presentations
One of the more regular moans I get to hear during a conference or corporate event is that the speaker can't see their speaker notes on the comfort screens.
Then there are other speakers who struggle with having cards in one hand and a clicker in the other.
I've found a way of eliminating both problems with an iPad mini because you can use one as a presentation controller and a comfort screen all in one.
How? By using the Duet Display App: https://www.duetdisplay.com/
Just a tiny Speakery tip. Hope this helps.