There are benefits to running tests locally, such as quickly checking the quality of code and running manual tests for one-off issues. However, there are drawbacks to relying solely on local testing, including reduced browser support, lack of coverage across different browser/OS combinations, testing becoming a bottleneck, and a lack of accountability for mobile devices. These limitations can result in poor app quality and slow release times. To overcome these challenges, it is recommended to execute tests through an external test infrastructure, such as the Sauce Labs Continuous Testing Cloud, which provides comprehensive coverage, scalability, and analytics to ensure high-quality app delivery at scale.