I think Zeffs logbook would have been valuable just for the knowledge. Like how log poses work, the islands he saw. Issues he had, key people etc. So if you came across those people or places you'd have an advantage and some warning. I always saw it as a 'knowledge is power' type thing.. and Luffy is like "Books? Who reads books?" Lol
The grand line feels like a place where travel is insane... so when your born in the grand line thats just where you live haha I will say i really like how the grand line works, such an interesting world :) welcome to the grand line man!
Officially, in an SBS, Zoro drinks the most in the current crew while Nami is close second. Usopp and Luffy aren't big drinkers as they are the most child-like. Luffy did say he doesn't drink alcohol (or doesn't prefer it) when he was in Loguetown. He instead drank milk. In the live action too, he ordered milk while others ordered beer, which I found really cute and funny 😂
*SBS in the manga are questions from fans that Oda answers. They contain additional information, lore, or just random facts about the crew. I think you can find them online depending on what anime episode you are. Maybe.