What are two possible use-cases for a FlexCard?

FlexCards are designed to present contextual information at a glance and expose relevant actions that users can execute directly from the card. Salesforce defines a FlexCard as a configurable information block that combines pertinent data with links or actions for processes within a specific context.

This makes option B a valid use case. A FlexCard can retrieve and display information from one or more configured data sources and summarize complex or related data into a concise, quick-glance user interface. Salesforce also documents FlexCards as presenting contextual data and actions together. Option D is also appropriate because FlexCards support numerous actions. Administrators can configure them to launch an OmniScript, navigate to another page or application, display a flyout, trigger data operations, or initiate other supported processes. A homepage FlexCard can therefore provide shortcuts into commonly used workflows. A multi-page questionnaire is more appropriately implemented with an OmniScript, whose primary purpose is guided interaction. Likewise, although FlexCards can support actions and data updates, complex inline tabular editing and calculation is not the primary use case represented here.

Study Guide References: OmniStudio FlexCards; Contextual Information; Data Sources; FlexCard Actions; OmniScript Launching; Quick-Glance User Experiences.