I am not a pro and never will likely be one, I shoot because I enjoy it. I use my 256GB iPad Pro to edit my images while I am traveling. I can always edit it again when I am home and use my 27" iMac but sometimes you really want to see what you have captured before you are heading home. Is it the best machine for the job, probably no and I wouldn't want to be using it for images I was being paid to take, but for my needs it works well. I use an adapter that allows me to insert my SD card and directly transfer. My camera is a Pentax K-3 so the files are not small and the transfer time isn't excessive. If you use a third party device to transfer the images be prepared to wait a long time. Apple also makes a camera connection kit with allows you to use a USB cable to connect the camera to the iPad. Neither are cheap but then neither was the iPad or the camera. The difference between transfer speeds makes the third party adapters a poor investment.

Stevi