If you're not convinced yet, freelance Content Marketer and blogger Mike Farmer has some interesting points for you.
One thing I would add to his post is the importance of creating a Content Curation hub to really capture the benefits of your Content Curation efforts. Sharing links is just not going to be enough: in a world where tweets have a very short lifetime, you need to give your curated content a second chance by putting it on a curation layer where it can be discovered from search and from people with similar interests.
This can be a blog, a site or a Scoop.it page but if you're going to make content curation part of your content marketing strategy, you will need that long term repository that social networks don't bring.