The newer iPad Pro model with the keyboard cover seems like it would be much better for productivity tasks than an iPhone, for example. Still nowhere near as functional as a laptop for day-to-day productivity - but maybe good enough that you could bring an iPad along on a trip and make a quick edit or restart a server if needed, and leave the laptop at home?
Simply things like a booking agency sending him a PDF contract to sign becomes a saga of jumping between multiple apps, importing and exporting etc. in order to get it done and sent back. Sending sound clips to his customers is also surprisingly difficult, as there is no easy integration between services like SoundCloud and DropBox, and even with the new 'Files' app, it is difficult to manage more than a few files in a complicated folder structure and send them on to others easily.
He also found it a challenge to make simple posters etc. for his upcoming shows and send them to printers or even to Facebook. Supposedly simple acts like adding readable text to a photo background was a challenge, and he ended up going through about 6 different apps before he found one that worked the way he wanted to.
Add to that the fact that his iPad Pro pen started to fail after a couple of months, and I think he has regrets going down this path.
The keyboard cover was super handy (I highly recommend it), and I admit that there are some cases where I could have gotten away with just an iPad. But for anything important, I'd need to open a VPN and RDP session anyway. A Surface may have been a better purchase, TBH.
Thats the trick... :(