In short: According to Google Assistant's support page, the smart assistant now supports over 10,000 smart home devices from over 200 different brands. That is actually a pretty big deal, seeing as just this past May it was only at around 5,000 devices. But now it has 10,000 devices that it supports, but it is still lagging behind Amazon Alexa, which supports over 20,000 smart home devices.
Background: Google Assistant has been playing catch up to Alexa, pretty much since it launched a little over two years ago. Alexa had a pretty big jump start on Google and even Apple, when it came to smart speakers and smart home connectivity. For a while, many have said, for smart home control, Amazon Alexa is hands down the best. And that is simply because she supports so many more devices than Google Assistant and Apple Siri or Homekit. But that won't be the case pretty soon. At the rate that Google is adding more devices, it will have caught up with Amazon in just a few months time. The list of devices in the Google Home app shows just how many devices are supported by Google Assistant, and it's a pretty long list. So the majority of products are already supported, but there is still room to grow, for Google Assistant.
Impact: This means that whatever smart home device you pick up now, it will likely support Google Assistant. For a while now, though, new devices have been supporting the big three: Amazon Alexa, Apple Siri/Homekit and Google Assistant. These basically need to be supported for the device to actually sell well. As it means that it will work with any platform. Whether that is iPhone, Android or Amazon. Controlling these smart home devices with your voice is definitely a nice feature to have, and it will definitely be getting more popular as time goes on.