Absolutely. In my experience, most unforeseen issues are related to performance at scale with unexpected data (the kind that seems to only ever crop up in produ

Absolutely. In my experience, most unforeseen issues are related to performance at scale with unexpected data (the kind that seems to only ever crop up in production, and is really hard to design a load test for). Performance issues in the browser are rare, and have nothing to do with the number of users using the application.