HRMS are indeed necessary if you want to devote your time in observing the firm's performance instead of making calculations of employee's leaves, wages, working days, working hours, check-in, check-out timings, employee record and performance and there is much more to do.
Easiness: HRMS ease and lowers the manual work, keeps it simple with sorted records of each and every working employee.
Maintenance: The data could be hard to handle if maintained as a hard copy. Hence, it eases the handling and maintenance of records.