Actually I agree with you. I trust the contents that I saw in my Email compare to what I saw in Social Media. For me, I never encountered scam or malicious applications in the history of my Email usage. The security patches in Email sites are more rigorous than Social Media, or maybe scammers are far more interested penetrating sites that many people constantly and interactively participating like Facebook, Tumblr, Twitter, Instagram and many more.
For security, I think email is more promising, but for marketing and advertisement Social Networking Sites are more effective. Many people can see and be aware of what you are posting. Easy to share and repost. They can see your advertisement just unintentionally or just by browsing their friends or followers activity. Some uses tickers, a very helpful feature of Social Media. Those privileges are not present in Email.
For me, you can try advertising in Social Media by putting catchy posts, images and/or videos and adding your Email for inquiries. On the other hand, if you want to use and concentrate using Emails there are three things we can do: Consistently send information and details to all of your contacts (we just hope that on their end it will appear right on the Inbox tab, not on Spam. We cannot control those.), second is ask your message recipients to forward the information to their contacts and raise awareness of your business and lastly, reply interactively to the inquiries, build relation and recommend your item, product or services to them.
You can use either Email or Social Media, but I suggest you use both. Just take extra precautions in Social Media and assure the readers that your business is not one of those scams circulation over internet. Best of luck!