Is World Adventures worth buying?

In my case, definitely yes. I have done countless vacations, mostly to Shang Simla, which is just beautiful in this game. This, ironically, means that I don't even consider the nectar making or the photography in my decision. Photography just clogs up the savegame, which is why I avoid it. I have yet to try nectar making. Martial arts are quite fun, and the time in your vacation home is a time away from your daily chores, which can be particularly busy for children and teens. It's also a time out of time, as your world at home is frozen while you are gone, and such is aging. I also like the "tomb raiding" part, at least as long as it doesn't devolve into a complete trap fest.

Keep in mind though that you should have the appropriate NRaas mods (here, aside from the general bug catchers, mostly Traveler) in place, otherwise you will probably experience all kinds of bugs during transitions, like lost inventory items, stuck pregnancies, sometimes lost sims, etc.