With in-built tools for sending bulk emails you can send targeted mails based on specific criteria defined via filters.
Re-marketing email campaigns helps to get more conversion by offering customers more discounts, reminding them about incomplete orders or just to say Hi!.
These day everyone who is using internet has a email ID and if they have it then you can reach it easily.
It costs less than $0.01 to send an email and the returns are very high.
For every dollar spent on the email marketing you will get $44 in return and thats a pretty high return on investment.