flow vs function

by flow

flow do
  # Flow arguments allow you to parameterize the flow
  argument :org_name, :string do
    allow_nil? false
  end

  argument :user_name, :string do
    allow_nil? false
  end

  # The flow returns the result of the `:create_user` step.
  returns :create_user
end

steps do
  # The step is called `:create_org`, and it creates an `Organization` using the `register_org` action.
  create :create_org, MyApp.Accounts.Organization, :register_org do
    # The input to the action refers to an argument of the flow
    input %{
      name: arg(:org_name)
    }
  end

  # The step is called :create_user, and it creates a `User` using the `:register_user` action.
  create :create_user, MyApp.Accounts.User, :register_user do
    input %{
      # The input refers to an argument of the flow
      name: arg(:user_name),
      # and to the result of another step
      org: result(:create_org)
    }
  end

  # The step is called :create_blank_project, and it creates a `Project` using the `:create_example` action.
  create :create_blank_project, MyApp.Accounts.Project, :create_example do
    input %{
      # The input refers to the result of another step
      org: result(:create_org)
    }
  end
end

by function

def create_user(org_name, user_name) do
  org = MyApp.Accounts.Organization.register_org(org_name)
  user = MyApp.Accounts.User.register_user(user_name, org)
  MyApp.Accounts.Project.create_example(org)
  user
end