reasons why restricting users to MS Authenticator would be preferable
As a security professional:
Under most situations, it is equally as good as any other 2FA app.
Within the Microsoft ecosystem, it provides additional security features above and beyond simple 2FA.
If your workplace is leaning heavily on the Microsoft ecosystem, especially their cloud offerings like Azure, then restricting employees to the Microsoft app is a no-brainer, and actually quite reasonable.
For example, if they happen to have a hybrid domain with an on-prem domain controller syncing with Azure (forgive me for using obsolete terms, I’m a greybeard), then they can control all access to all company assets, including 2FA. If an employee leaves the company, they can also disable the Microsoft app at a moment’s notice by disabling the employee’s Microsoft account. Because everything is hooked into Azure, it sends push notifications down to all company assets - like the Microsoft 2FA app - to unhook all of the company’s credentials and prevent employee access after the fact.