You can tag your friends easily by using Auto tag friends option in Campaign's Overview tab > Advanced settings > Facebook tab. There's an option that allows you to choose how many friends to tag in each post and probability in %.
Tip: Don't use it too much, Facebook has the limits for this too. You could get blocked from tagging users if overused.
And yes, your friends will see the post, I mean, they'll get the notification that you're tagged and most probably check the post.
Is it good for marketing? Well, depends. If you added targeted friends, if they're interested in what you're posts are about, then it's good. If you have added bunch of random people as friends and promote something they're not interested in, it will only have negative effect, they'll remove you from friends or maybe even report your account.