There are so many jobs in various industries where professionals have to send emails in bulk.
Marketing - To sell some services or products. This one is the most popular and always assumed
Procurement - For many businesses, it's compulsory to send emails to announce important decisions and events happened. For example, you receive privacy policy notifications from companies.
Process - Enterprise processes need email notifications for reminders of tasks, events, and many other types of notifications
Newsletters - this one is also popular
Regardless of what use case you have to send emails, you have to use some free/paid tools in your daily life to send emails.
While using these tools, why are you not so happy with them?