Apple Apple Watch Ultra customizable action buttons can launch shortcuts and also support these features

Assigning dedicated shortcuts to action buttons can also pave the way for additional adaptive features. For example, shortcuts with location- or time-based actions can allow action buttons to perform different functions throughout the day.

Subsequent Multifunctional Use

Depending on the application the action button is used to control, Apple Watch Ultra users will in some cases be able to select additional actions for subsequent presses.

Apple envisions people using the action buttons without looking at the screen, so subsequent button presses should be logical from the first press and also make sense in the current context.

For example, a workout app might let the user start a triathlon on the first button press and switch to another segment on subsequent presses.

It's worth noting, however, that apps won't be able to assign functions to long-press action buttons, as watchOS 9 reserves that interaction for emergency SOS functions.