Interactive content changes the recipient’s experience of an email. As well as increasing viewing time, it can increase motivation to click or take action.
Showing additional content creates intrigue and encourages recipients to engage on a deeper level with the email.
An image viewer can show more detail of a particular product, or more products, increasing CTR and conversion. This enables you to show the recipient more at a key position within the email without increasing its overall length or the need to scroll.