It's secondary function is to properly fix and place tasks that you might sync from 3rd party apps like monday or clickup. Things that can be added are like color, duration along with time preferences and priority level for the schedule assist. Semantic search helps in copying over these values from a previous similar task or from a tag that has default values for these attributes (automatically using zero shot classification based pretrained model).
The $3.5 plan is not recommended for work calendars. It reorganizes all events into 30 minute parts when the scheduler runs and then joins them together before updating your calendar. You want the $6.50 one with 15 min accuracy to allow more flexibility. The $3.5 is for personal use cases.