Service call with tempate entity_id not working as expected

Configuration
1

Can anyone please help explain why this automation doesn’t work if use a template to lookup the entity_id

- alias: "Socket Timer Started"
  trigger:
  - platform: event
    event_type: timer.started
    event_data:
      entity_id: timer.socket_timer
  action:
    service: switch.turn_on
    target:
      entity_id: "{{ states('input_select.power_sockets') }}"

but this version where I do the same thing using a variable does work

alias: "Socket Timer Started"
  trigger:
  - platform: event
    event_type: timer.started
    event_data:
      entity_id: timer.socket_timer
  variables: 
    target_entity: >-
      {{ states("input_select.power_sockets") }}
  action:
    service: switch.turn_on
    target:
      entity_id: "{{target_entity}}"