Explain what enabling app insights on web app does
One can create a web application that would report to AI without ever enabling it in Azure portal: just install appropriate packages, initialize the library with instrumentation key and you are done. You don't even have to run the app in Azure, the data is still going to be sent to AI regardless.
With that, it is unclear why there is a separate "enable Application insights" button in portal and what it does. There is no documentation linked that explains what exactly happens when it is enabled there and why is there a need to enabled it. It would be nice to provide some details instead of a blank page with "Enable" button.