As a person of limited knowledge & even more limited memory, I've found my digital camera truly excellent as a note book.
Started 6 or 7 years back when I lived in the US. Saw a plethora of engines I'd never seen before, & many which I couldn't recognise.
As digital photographs have an incremental cost of zero I got into the habit of recording all background info for unknown or unusual engines. For these, I always shoot the engine number plate up close (good way to engage owners in conversation & learning more, as u may need to go round 'tother side...), & also any descriptive material.
My camera focusses down to 0.8 inches for that minute detail you might want, and most digitals focus very close. Fill-in flash can be very useful when shooting into the sun, to illuminate detail hidden in dark shadow. Not normally helpful with anything behind glass or cellophane -- reflections can be too distracting.
This info record has proved invaluable a hundred times over for research, & to ensure I didn't need to try to remember too much in any one day....
Also hepful to others when looking at your pix on the web -- saves u time on labelling, & they can see the data for themselves.
I suspect the only reason we don't see everyone using the camera as a virtual notebook is that we have an emotional throwback to "film + processing costs money". Almost any digital, right down to the =A335 Tesco's specials, will do the job well.