There is probably no human user who needs access to every corner of a company's task management tool. Teams need private spaces to collaborate and triage, and permissioning is the solution to access management. This is why service users exist.
Using a service user keeps real users from receiving irrelevant notifications and emails, and it ensures that access controls remain in place.
In the event that an employee leaves the company, having used a service user to connect a tool ensures continuity for any integrations.