Yes, Performance Appraisal is normally used as a tool to award/reward increments, promotions, etc. However, the performance appraisal system is a system that needs to be looked at scientifically. Actually, this system helps an organization approach managing the performance of individuals holistically. By this, apart from deciding increments, there is an opportunity for the employer to understand how good the individual is in his current position, potential to shoulder or manage higher responsibilities, career planning, succession planning, etc.
However, many organizations do not take this exercise seriously, and only during the annual review, this is done hastily and handed over to the HRD department. By this approach, the whole purpose is defeated.
Increments are not mandatory. There is no legal binding on an organization that they must extend an increment to the employees. An organization hires someone to perform certain functions for which it fixes up a mutually agreed remuneration. As long as he does this to the satisfaction of the organization, the organization is bound to pay him the agreed remuneration. However, there may be chances that the employee does not perform well in the given portfolio (as intended), then the company can look at this differently.
Therefore, paying an increment comes only when you excel well in your performance, contribute more to the organization, and demonstrate a high degree of potential to take on more and higher responsibilities. So, considering someone in that position and paying a higher salary is more relevant in this case. And it is in this context that the Performance Management System has come into play to assess his suitability.
Otherwise, there is nothing that would hold you back from delinking your increment system from the Performance Appraisal review.
Regards,
Balaji