Template condition in script

Configuration
1

I’m wondering if it’s possible to use template condition in a script’s sequence.
My current setup goes like this:

alias: "Update HA"
sequence:
  - condition: state
    entity_id: updater.updater
    state: 'On'
  - service: shell_command.update_hass
  - service: homeassistant.restart

Which has no issues at (other than not working because of the incorrect condition), it validates the config correctly
However, when I change it to this:

alias: "Update HA"
sequence:
  - condition: template
    value_template: '{{ states.updater.updater is not None }}'
  - service: shell_command.update_hass
  - service: homeassistant.restart

I always got this error: 17-01-31 12:24:39 homeassistant.bootstrap: Invalid config for [script]: [condition] is an invalid option for [script]. Check: script->script->update_hass->sequence->0->condition. (See /home/hass/.homeassistant/configuration.yaml, line 123). Please check the docs at https://home-assistant.io/components/script/

I’m not sure why that is happening, as the error message says condition is not valid there, but in the first example it is.
If it’s the template condition that’s not possible I guess the error message should be something different