Preventing resource starvation: Some denial of service incidents are caused by errors in software or configurations in the system, which causes resource starvation. Such attacks are referred to as friendly-fire denial of service. One of the common use cases of rate limiters is to avoid resource starvation caused by such denial of service attacks, whether intentional or unintentional.

Managing policies and quotas: There is also a need for rate limiters to provide a fair and reasonable use of resources’ capacity when they are shared among many users. The policy refers to applying limits on the time duration or quantity allocated (quota).

Controlling data flow: Rate limiters could also be used in systems where there is a need to process a large amount of data. Rate limiters control the flow of data to distribute the work evenly among different machines, avoiding the burden on a single machine.

Avoiding excess costs:

https://www.cloudflare.com/learning/bots/what-is-rate-limiting/