When to use Flow Designer vs Workflow?

Workflow can be used in following cases:
1. If the process requires complicated or scripted logic, it can be written in a Workflow.
2. Changing logic already developed using Workflows.
3. SLA timer is required.
4. Steps required do not exist yet in Flow Designer and require unsupported protocols.

Use Flow Designer when:
1. Process owners need to use natural language and low code way to automate approvals, task, notifications and record operations.
2. New logic needs to be developed and it has not been created in workflow.
3. Business logic needs to use the library of reusable actions across multiple flows.