In the documentation, it looks like the state is displayed for the entity on the button (colored icon):
I am using the button card on an input_boolean sensor. And when using the button card, the card does not show the state (on or off). I can’t find a parameter for this functionality in the documentation, but the picture used in the documentation displays the status of the light (on/off).
Take a look at this custom card: https://github.com/kuuji/button-card, this works great with input booleans and provides even further customization options.
I am holding back on the custom cards for now. I believe HA will be updated with a "Card Store", so waiting for that, so updates/fixes will be automatic.
In the meantime, the standard cards should have some basic functionality as the documentation shows. Hopefully this will be fixed.
The default theme (i.e. you haven’t changed the theme) has state based icon colours. I have seen some themes that don’t have this though. Which is why I asked.
Yeah… You need the custom-button card. They decided to only support the colour change for states for things like lights and switches (because they consider yellow to mean power)