I concur that increasing one’s first aid skills is a good way to carry knowledge instead of stuff.  Rather like many backpackers packs get heavier (due to acquiring more gear) before they get lighter (through better and more-multipurpose gear and greater knowledge), Many people, after witnessing or having an accident, bring larger and larger first aid kits.  As they get more training and see more incidents, they realize you can do a lot with other materials.  And that store-bought first aid kits have the worst usefully/weight possible.
As I got more training and as I’d successfully handled more actual injuries, my fear of accidents diminished and my confidence in making due with improvised materials increased.  And funneling one’s awareness of how injuries happen into decreasing risky behaviors is always better than carrying stuff to deal with an injury that could have been avoided.
.
