Hi, Do you think both "Google plus Pages and Google plus Community" are helpful to promote your blogs?
Yes. can be helpful for creating links and bringing traffic. How long the links remain as dofollow is unknown though. As with everything else, they will change that eventually. Currently they are dofollow because Google is trying to get people there.
Yes, they can be helpful.. But just like anything else, if you over-spam it, it will work against you.