The werewolf world is perfectly usable but you will see werewolves in moonwood mill. You can change all lot types and build whatever you like. If you keep the bar lot type, other occults will also spawn when you visit the bar. In the world there are two werewolf hangout spots where werewolves will gather so you will see them. You can turn off werewolves for all other worlds so the pack is absolutely not intrusive. But moonwood mill is occult terrain.
You could set the moon phase to be permanent new moon or any other moon fase that is not full moon. That way you can avoid full moon werewolf rampages. Rampage due to temperaments can't be avoided. Perhaps you could cheat the temperaments on existing werewolves. You could give them the 4 positive blue temperament so they don't build fury. Carl has a mod that makes this easier if you don't like typing cheat codes.
I don't know any features outside off the werewolves that can be used. Perhaps the collectibles but I don't know how successful a non-werewolf is in collecting them. On the bright side there are no intrusive features to disrupt your game. The only other thing that came in the pack is a small telescope but that was patched into base game. I wish they would followed the same principle for the infant changing table.
Werewolves is totally unrelated to body hair. Body hair wasn't even in the game when werewolves was released. Body hair came with high school years and that's the pack that makes body hair grow. I have the werewolves pack but not high school years. New sims in CAS occasionally get body hair but it does not grow in live mode. Newly generated spellcasters in CAS get an insane amount of scars, so having to remove them in CAS is a small downside.
As for the comparison with growing together: the world is bigger but only the neighbourhood with the community centre has fishing spots, swimmable water and walking paths. The rest feels rather empty with very few walk by Sims. Moonwood mill feels more alive. On the gameplay side is growing together more intrusive with social chemistry, family dynamics, self discovery moments, midlife crisises and npc's inviting themselves over for sleepovers. I like it but it is one of those packs you will notice in regular gameplay. The only game mechanics you can turn off are self discovery moments and sims getting fired from work. Also infants are more difficult to play with growing together because they don't start with the ability to crawl and sit in a high chair like they do without the pack.
As for the comparison to vampires, I think they are very similar. You don't have to interact with the werewolves but they are there. You will notice werewolves a bit more in their own world but you can force them to act human in every other world.
