I prefer social media marketing than email marketing. Social media has its own advantages like your content can be viral for a long time, you can make relations or connections and can communicate or share with them in future.
Email marketing is directly marketing a commercial message to a group of people using email. In its broadest sense, every email sent to a potential or current customer could be considered email marketing. It usually involves using email to send ads, request business, or solicit sales or donations, and is meant to build loyalty, trust, or brand awareness.
Both E-mail marketing and social media ads have their own relevance and give results according to the efforts. If we implement both with strategy then it can work wonder for promotions and lead generation.