Software that behaves differently based on a user's location or network needs to actually be tested from those different vantage points, which is where proxies fit naturally into a QA workflow.
Testing geo-specific behavior
If an app shows different pricing, language, or feature availability by region, routing test traffic through proxies in each target country lets QA verify that behavior without physically being in each location.
Simulating varied conditions
Combining different proxy locations and speeds with test automation frameworks helps surface bugs that only appear under specific network conditions or from specific regions, which a single office network would never catch.
Keeping it separate from production
QA proxy usage should stay clearly separated from real user traffic and any live production systems, both to avoid unintended side effects and to keep test data cleanly distinguishable from genuine usage.