[thesuitonym]

People really don't understand 2FA codes. Imagine trying to tell thousands of students to get the code from their 2FA app (Which app?). What happens when a student goes home over the summer and gets a new phone, but doesn't transfer the app info? Duo offers a level of management that other apps don't. If a student is struggling, you can send them a text with a direct link to the app they need to download. You can temporarily bypass 2FA from the Duo console. For the longest time, it was the only 2FA app that offered any kind of management. Okta has it now, too, but most higher ed already has a different SSO provider, so switching to Okta just to get 2FA management (And I'm not sure it's as good as Duo's) is probably an impossible task to get off the ground.