Providing an opt-out option in email marketing is essential for several reasons. Firstly, it ensures compliance with various data protection regulations such as GDPR, CAN-SPAM, and others. Secondly, it helps maintain the trust and respect of your subscribers, which can ultimately lead to better engagement and higher conversion rates. Lastly, allowing users to opt-out helps to keep your email list clean and focused on those who are genuinely interested in your content.