The Echo Show was first introduced last year, and at the time of release included support for YouTube videos. However Amazon decided to stop selling Google products including the Google Home and Nest devices. Google then stopped the use of YouTube on the Echo Show and Fire TV. So many Echo Show owners were left with out YouTube support - one of the reasons to own a Smart Display.
Apart from the lack of YouTube the Echo Show can do most of the home control, video calling and audio streaming functions that the Google Smart Displays can now do. You can watch movies or TV shows from Amazon Video and Prime Video using the screen on your Echo device. Compatible Echo devices can play movies and TV shows from your Amazon Video library and programming from your active Amazon Channels subscriptions (like Showtime, HBO, and Starz).
You can make video calls to other users with Amazon Echo Spots, Echo Shows or the Alexa app on their device.
For music streaming you can choose from Pandora, Spotify, TuneIn, iHeartRadio and many others. There is no line out for connecting to a better loudspeaker system. You can however link to one via bluetooth. Amazon don't offer the equivalent of a Chromecast Audio dongle to allow streaming of music directly to your loudspeaker system.
You can view your security cameras on the display by requesting to see them.
Being an Amazon device you can ofcourse easily add to shopping lists.
With an Audible app subscription you can listen to audio books on the Echo Show.
With multiple Echo devices in rooms around your home you can stream multiroom audio easily. The speaker also allows the adjustment of treble, mid and bass just by using your voice.
To get the most out of an Echo Show you will really need to have a Amazon Video or Prime account.