Beyond that it's legitimately useful for logging into a second account on a site or for various testing purposes as a web developer. Though if you're consistently using it for the former, containers are a better solution.
Also useful for testing links that might only work if signed in.
For instance, if I share a link to a OneDrive file, will it force the receiver to sign up with Microsoft before they can view the file.
Absolutely! I do that all the time.
Beyond that it's legitimately useful for logging into a second account on a site or for various testing purposes as a web developer. Though if you're consistently using it for the former, containers are a better solution.
Also useful for testing links that might only work if signed in.
For instance, if I share a link to a OneDrive file, will it force the receiver to sign up with Microsoft before they can view the file.
Absolutely! I do that all the time.