I start to appreciate more photos as an addition to drawings. If illustrations are imperfect. photos capture better the jizz of a bird. Useful for tropical species where there are multiple similar brown insect-eaters or greenish weaver-likes which are unfamiliar to you.
I also made a progress from paper guidebooks to electronic ones. One hot sweaty afternoon in New Guinea I decided I hate carrying the book. I sat down, waiting for some non-existent kingfisher, and took pictures of every plate with my mobile. It took maybe 30 min, worked surprisingly well and we never carried the book in the field ever since. Then at the airport, I did the same with The Birds of the Indonesian Archipelago. Worked well, and the book stayed safe in the hotel room. In future we plan not to take paper books even as an insurance, because we have multiple mobile phones between us.
Doesn't bother you how cumbersome electronic devices are compared to a book? I will always find the right page faster in a book if I am familiar with it and I can easily see a lot of pages basically at once or quickly flip and an A5 paper has an order of magnitude more resolution than any display ...