The physical constraints of its hardware impose certain limits on the performance of a single computer. Moreover, it is extremely expensive to improve a single computer’s performance after a certain point.

Solution

We can achieve the same performance with two or more low-spec computers as with a single, high-end computer. So, distributed systems allow us to achieve better performance at a lower cost.

Note that better performance can translate to different things depending on the context, such as lower latency per request, higher throughput, etc.