Bulletpoint summary
A well-maintained IP with a high reputation is one of the most precious assets you can have as a sender. As your reputation rises, your email's chances of reaching the inbox increase. If you have your dedicated IP, it will be easier to troubleshoot the root cause of deliverability issues and request whitelisting of your IP from some external postmasters.
A dedicated IP provides additional control over delivery
Having their IP's reputation defined by the acts of others, they become the sole determinant of whether or not their emails get delivered.
Depending on your volume and sending habits
You might have a large number of dedicated IPs to manage your email traffic to the best of your ability. If you send above 200k emails per month, a dedicated IP is recommended. SMTP Server can distribute and manage your volume over multiple IP addresses to ensure optimal inbox placement.
Many clients choose a dedicated IP over a shared IP
Since they don't want a sender suffix like emailer.hubspot.com attached to their emails. The email service provider sends all emails on behalf of Company X while using a shared IP. Dedicated IPs appear to originate solely from the company's email address.
How a Dedicated IP Affects Deliverability
Making a bad first impression will stick with you for a long, long time
You are responsible for your reputation when you use a dedicated IP address. First impressions are important, and making a bad one (e.g., sending a broken link in an email, failing to follow proper IP warming procedures, etc.) will stick with you for a long time.
This means that if you do something to harm your ISP's reputation, it will take time for them to trust you as a sender again. As a result, inbox placement and deliverability will be affected.