Salesforce rapidly enhanced Flow’s functionality and encouraged all its customers to move from Process Builder and Workflow Rules.
Salesforce plans to retire Process Builder and Workflow Rules sometime. Salesforce rapidly enhanced Flow’s functionality and encouraged all its customers to move from Process Builder and Workflow Rules. Even the advice on which automation tool to use has an updated message written by Salesforce Help or Trailhead; the message reads as:

“For all behind-the-scenes automation needs, we recommend using Flow Builder.” Trailhead: Choose the Right Automation Tool