Use templating to enforce consistent entity naming

In order to force myself to have consistent naming I would like to use to use templating/variables when I use a blueprint. If the entities do not exists that might be an indication that I gave them an entity_id that is not according to my naming convention.

The following does not work without altering the blueprint. Why is it that I can’t use (limited) templating here?

---
alias: Some automation with motion/lux multi sensor

# for every room this is the only part that I would have to edit
variables:
  room_name: kitchen
  light_type: spots

# this would be the same for each room
use_blueprint:
  path: some/path.yaml
  input:
    target_entity: "light.{{light_type}}_{{room_name}}"
    motion_sensor: "binary_sensor.motion_{{room_name}}_occupancy"
    illuminance_sensor: "sensor.motion_{{room_name}}_illuminance_lux"
    illuminance_cutoff: "input_number.{{room_name}}_treshold_lux"
    no_motion_wait: "input_number.{{room_name}}_timeout_shutdown_light"