Feature A
Here’s the sales pitch: Home Assistant is an open source program which brings together all your smart and IoT devices and allows to track, record, automate basically anything.
Example:
Plug your dishwasher into a cheap power measuring plug and then add an electricity usage threshold sensor in home assistant. This way you can detect if the dish washer is running or if it finished. You can then send a notification to your smart phone telling you it’s done.
You could also have it add a +1 to your “Run the dish washer daily” goal on Beeminder 
Feature B
Home Assistant also has powerful dashboard where you can combine all your devices, sensors, arbitrary RSS feeds, etc. into a nice to look at dashboard that you can interact with. Some people even put up a tablet on the wall showing this dash board 24/7 so they have an overview of their house, energy consumption, the weather forecast, etc.
Imagine having Beeminder goals as part of that dashboard! Things like that are actually really common. For instance, Home Assistant integrates with a lot of routers showing which devices are currently in the network. Or as mentioned previously: It, by default, shows the weather forecast for your location as part of the dashboard. You can also easily integrate an RSS feed and use jinja2 for turning that into markdown which in turn is rendered nicely in the dashboard.
I’d love to see both a) and b) done