Though, ive met a few "lookin in books is faster" folks. They gave up after the tenth time of taking about 5X longer than me to just do a digital search.
So, with respect, the condescension here is really annoying. Speed-of-lookup alone is not the relevant metric, which Is why I spoke in terms of
engagement with players, which is the real job of the GM.
My most recent campaign was D&D 5e -
The Wild beyond the Witchlight. I had the Beadle and Grimm's Silver Edition as a physical copy, and D&D Beyond with an electronic copy, and all the PC characters and game rules in D&D Beyond. Plus, I was working with Syrinscape to run soundtrack - so the laptop was going to be there regardless. It was a prime moment for me to move to all-digital reference, but... it just didn't work that way.
For example, every time I needed to work map-and-key, the physical copy was superior - because I could have the map(s) on the back of my screen, and the key and room descriptions laid out in front of me - an effective real-estate several times what my 17" laptop could produce. When I tried, any gains I may have made from the supposedly faster electronic lookup were lost in flipping among windows and tabs trying to correlate different elements in realtime. Map in one tab, monster stat block in another, room description in a third, spell effect lookup in a fourth...
It got old, really fast.