Here in the films they make you believe all he quaffs are variations on the martini. Bourbon whiskey doesn’t quite have the same ring to it. I’m surprised Sake appears as his #2 preference. Drinking a hot alcoholic beverage seems... bleh (of course, I don’t drink, so...).
You have to remember that You Only Live Twice is the novel after OHMSS, Bond is still an emotional wreck, then he is sent to Japan.