What’s the difference between using automation for a set time, and a timer? (difference between adding timer and timer in the app)

The KASTA app offers both Timers and Schedules. A Timer allows you to turn on or off KASTA devices after a set period.
This can be enabled/disabled through the App. KASTA smart relay devices also feature onboard control to enable/disable timers.
A Schedule allows for automation to occur within a set time.
You need to set up a schedule to turn on/off the device/group/scene and a second schedule to perform the opposite action.