An unsubscribe indicates that a recipient opened and clicked your email, which are positive engagement signals for email providers. Making it difficult for users to unsubscribe is more harmful, as frustrated recipients will mark your email as spam, which severely damages your sender reputation.
Marketers should not view the promotions tab as a penalty. Email providers like Gmail are correctly categorizing marketing content where users expect to find it. Trying to game the system to get a promotional email into the primary inbox goes against user expectations and the provider's goal of a clean, organized inbox.
Contrary to popular belief, common marketing words like "free" in a subject line do not inherently cause emails to land in spam folders. Spam filters are more sophisticated, looking at broader sending patterns and user engagement rather than just flagging specific keywords in isolation.
While dedicated IPs offer control, marketers with smaller lists may struggle to generate enough volume to build a strong sending reputation alone. Using a shared IP from a reputable provider allows them to benefit from the collective positive engagement of other good senders, improving their own inbox placement.
If your sending practices tarnish your reputation, your Email Service Provider (ESP) may move you to a lower-tier shared IP address without your knowledge. This is done to protect their high-quality IPs, but it will severely harm your future deliverability, creating a downward spiral that is difficult to escape.