The most obviously useful way to control Logic Pro X from the iPad is to use the tablet's surface as a mixing board. This mode literally puts a bank of faders in front of you, up to eight at a time, and you can jump between different banks of eight faders at will. Manipulating the mixing board faders via iPad instead of a mouse and keyboard has one big advantage: thanks to the multitouch screen on the iPad, you can grab several faders at once and manipulate them in real time. On a laptop or desktop, you'd have to link several tracks together or else record fader automation one track at a time.
This for me is one of the big appeals of Logic Pro X, as I've been looking for a way to use the iPad to control recording levels live, and to quickly automate mixes for podcasts. I've been using Auria, which is great, but I'd love something that ties into a fuller production environment on the Mac.
There's a decent video overview of the iPad Remote features at the CNET link.