I use the ipad pro and apple pencil to draw from live models or my imagination. I organize figure drawing in my local community twice a week. all these sketches are done from life, without any tracing or using the camera. I use my eye. its much more challenging than copying a photograph and makes me a better artist to work this way.The sessions are timed, usually 10-20min, with the occasional hour long pose on sundays.
I also found the ipad to be useful in making low resolution pre painting color sketches for oil paintings. I often photograph a oil painting when i get stuck and work it on the ipad for a while until i like the direction its headed. then i finish the oil painting like the digital sketch. Sometimes i do a similar process for digital paintings that i import into a more powerful workstation later to finish the digital paintings so they can be printed on my 44" printer.
I hope the new ipad has more ram i would like to use it more on finished artwork, but for now its a nice light weight low resolution sketchbook.