I work primarily with Logic (been using it for 20 years) but the form factor of an iPad is pretty nice - it fits perfectly on music stands and laptops don't. If Macbook screens would tilt 180 degrees, all the way flat, you might be able to use them on music stands too - but they don't.

If you are both playing and recording a real instrument at the same time, having the iPad on the the piano/music stand in front of you is very useful. Many people use Logic Remote on iPad on the stand, and Logic on MBP for actual recording at the same time. But not sure why you should need two devices.

Touch screen is nice for some things too, like mixing or quickly toggling things.