Smart speakers are devices that have voice recognition technology embedded which enables them to interpret spoken instructions. This technology has been used in smartphones for some time (e.g. Apple's Siri) but is now being extended to smart speakers that can be used in your home. There are currently three main companies that are rolling out these devices, Google (Home), Amazon (Echo) and Apple (HomePod) and each brand has integration with their company's products,
As an example, the Amazon Echo (www.amazon.com/echo) smart speaker uses the Alexa voice recognition system and is orientated to providing shopping services on the Amazon shopping site, as well as streaming video and music from the Amazon platform. The same applies to the Google and Apple devices for their respective media platforms.
As well as providing information, they can also connect into some smart devices in your household to automate things, like turning on and off lights, or lock and unlock doors (with the right smart equipment). Google Home will integrate with the Google Calendar and can provide information about your daily tasks, as well as integrate with your entertainment system if you use a Chromecast streaming device. Google Home has extensive support for home automation devices so is probably a good option if you want to integrate with other smart devices such as air conditioners (store.google.com/product/google_home).
The Apple HomePod (www.apple.com/homepod) uses Airplay 2 to communicate with other Apple devices to manage audio and video streaming, and in particular, works well with Apple Music. So if you have a large library of Apple music then this is a convenient option for streaming music wirelessly throughout your house. The HomePod also has smart acoustic technology which manages directional sound for ambient audio or focused audio for directional sound.
There are benefits to these smart speaker, especially if you have a lot of the compatible technology in your house already. The convenience needs to be balance against the possibility of a lack of privacy. Given the revelations that have been made about the abuse of privacy recently though failures by some of the technology companies (most recently Facebook) it is a relevant concern about the level of trust we have with these listening devices and how that information is kept safe. I guess the risks need to be measured against the rewards so it is up the buyer to make that decision.