This isn't anything to do with digital time, it's just a convenience of recent microwaves. The digital microwaves of the 1990s did not have this feature, but they were still digital. If you input 1, you just got 1 second.

On microwaves that do have this feature, set the power first to bypass it.

Yes, they're different units. Just like how 1 month is less than 99 days and 1 pound is less than 99 ounces. That isn't a digital vs analog thing.