Depending on your application, you will have to assess whether testing on an emulated device or real device is the best option.
Many times it is not either/or decision and the best choice is both.
There are so many factors involved in both the options. Emulators offer the less expensive testing option, but they have many limitations for mobile testing and may not give an accurate depiction of the mobile user experience.
Whereas, testing on real devices gives the tester full functionality of the mobile device. While device types may be more limited than the emulated devices.
Testing. Everyone website or apps should do it. It’s time consuming. But unfortunately, it’s needed to ensure that your consumers have a positive experience when they use your site or mobile applications. And it’s important to make sure that the experience is a great one for every consumer every time they use your site or app. If fail to do a good job of testing and your customer will end up leave your site—and unlike your testing team, your customers don’t have the tools or the time to report back problems. And keep in mind that your customers don’t want to be treated like guinea pigs.
The aim of your web load testing efforts is not to find errors. Perhaps your developer has actually done a great job and did not make any mistakes. Instead, your goal in using load testing tool should be to understand the quality of your offering. Does it work? Does it function as expected? Will it meet the needs of your users, so that they come back again and again?