Template for _stateDisplay binary_sensor?

Configuration
1

HI,

on https://github.com/andrey-git/home-assistant-custom-ui/blob/master/docs/templates.md#change-on-state-to-activated @andrey instruction for templating the binary_sensor state display are as follows:

binary_sensor.motion_sensor:
templates:
# null will make the regular state-based logic to run.
_stateDisplay: if (state === ‘on’) return ‘activated’; else return null;

Is it also possible to show the value of another template?

I am trying to have it show the number of people home and show the value of the badge that has that number:

binary_sensor.grand_family_home:
  show_last_changed: true
  templates:
    icon_color: >
      if (state === 'on') return 'rgb(251, 210, 41)';
      return 'rgb(54, 95, 140)';
    _stateDisplay: >
      return {{states.sensor.home_badge.state}}

Unfortunately the sensor just shows Detected, as device_class Occupancy , which i have given it indeed because of the nice little icon:
14

the badge is : 21

leaving the device_class out and manually templating the icon works fine for the icon, but the state wont be displayed as desired:

15

2

My understanding is binary sensors will only display on/off. If you wish to change the text of state you will need to use the template sensor.

3

nope, not true. read the link provided. change the stateDisplay is perfectly possible. My quest here is to do that with a template instead of a fixed text.
58

binary_sensor.people_home:
  show_last_changed: true
  templates:
    icon: >
      if (entities['sensor.home_badge'].state === '0') return 'mdi:account-off';
      if (entities['sensor.home_badge'].state > '1') return 'mdi:account-multiple-check';
      return 'mdi:account';
    icon_color: >
      if (state === 'on') return 'rgb(251, 210, 41)';
      return 'rgb(54, 95, 140)';
    _stateDisplay: >
      if (state === 'on') return 'Occupied' ;
      return 'Vacant' ;

btw the binary_sensor here is a template binary_sensor, so it would really be in line with the rest of the sensor logic to be able to do that with a template :wink:

changing display to make it a little less serious:
59