WTH cant we use a variable or input field the define the value for a filter?

Month of "What the heck?!"
1

Why cant we use a variable or input field the define the value for a filter?
Like in the example shown her for max_value, tried al sorts of things, nothing worked so far.

  - platform: integration
    name: "Battery SOC"
    id: battery_soc
    sensor: wattage_calculated
    integration_method: "left"
    time_unit: h
    restore: true
    device_class: energy
    filters:
        - clamp:            
            max_value: 640
            ignore_out_of_range: true
2

I am pretty sure you can…

Can you show what you have tried? And provide detail on the use case?

3

See this thread