Why remove inactive users and employees
There are many SaaS applications that allow potential new customers to try the service with a trial period. Of course, not everyone will convert. At the end of the trial period, some will no longer use the service.
However, if nothing is done about it, their e-mail address and other (personal) data will remain in the database.
There are two reasons why it is necessary to delete old users. First, you want to keep the database as small as possible. This has many small advantages. Queries can be executed faster. The backup process will be shorter. Less disk space is needed, costs are lower. This may be a micro-optimization, since databases are very optimized in executing queries in even large data sets, and the disk space used is probably not excessive. However, the less work a server has to do, the better.
The second reason is more important: you want to keep only the bare minimum of personal data for privacy reasons. You should collect and store only the bare minimum of data needed to run the application. This protects users' privacy and minimizes the risks to the company in the event of a security breach.
If people, a few months after a trial period, have not subscribed, they are unlikely to subscribe. You no longer need their data.