They can send push requests that you can just approve on your mobile device, no typing in those codes. They also have backup methods that work w/o needing internet access on your phone.
I think institutions also use Duo because Duo takes care of the whole think whereas traditional 2FA isn't trivial to implement for the institution (generating tokens and all of that). At least that's what I was told by my institution when they made us start using Duo.
> takes care of the whole thing
But I would have assumed that there is considerable work necessary on the backend for a web server to integrate with Duo.
I think institutions also use Duo because Duo takes care of the whole think whereas traditional 2FA isn't trivial to implement for the institution (generating tokens and all of that). At least that's what I was told by my institution when they made us start using Duo.