Most Smart Home Assistant devices like Google Nest and Amazon Echo also double as Bluetooth speakers. You can pair Chromecast to use your Home Assistant as a Bluetooth speaker. The pairing will depend on your device, but it can be accomplished on separate Smart Home apps.  Smart Home Assistant devices provide good sound quality, and it is a good option if you aren't willing to spend money on a Bluetooth speaker. Moreover, you don't have to pair it with Chromecast each time you watch something on your TV. The smart home device will automatically pair the devices.