Lovelace: Entities card, type parameter only works with custom cards

Configuration Frontend
1

The Lovelace Entities card has a type parameter for each entity to set the card type to use to display this entity. This appears to only work with custom cards and not the built-in ones. For example, I was using the custom gauge card before it was included in HA and the following works fine

- type: entities
  title: My Phone
  entities:
    - entity: sensor.my_phone_battery_state
       name: Battery State
    - entity: sensor.stevens_phone_battery_level
      name: Battery Level
      type: custom:gauge-card
      min: 0
      max: 100
      severity:
        red: 0
        yellow: 20
        green: 70

and displays the battery level as a gauge. However, replacing type: custom:gauge-card with type: gauge simply displays using the default card. Am I doing something wrong, or does the entities card simply not support built-in cards for the display of entities.