The devices do work slightly differently, the Roku is connected to your Wifi/Internet and physically connected to your TV. You assign a dedicated Input, usually HDMI but they also support a composite video. It is initially configured over your LAN with a standard set of streaming channels, movies, sports, Youtube and NEWS. You can add or delete channels and configure network settings using the supplied remote control. With Roku there is no need for a laptop or PC to be connected but the Roku will accept a video stream from a computer or smart phone. When you first install your Roku you set it up with a user name and password and then as you add channels that you subscribe to, such as Netflix and Amazon you are asked for additional passwords that you already have for the subscription services, I think these services only allow you to stream to one device at any one time. Which brings me to the idea of using your PC/laptop as a server, the Roku allows the PC server to be added as a channel that is independant of the internet, any pre- recorded video on the server can be viewed by any device connected to your WiFi, a bonus is cloud storage where videos can be saved and viewed when you are away from home. Here is a comparison https://www.geek.com/tech/roku-stick-vs-google-chromecast-tiny-tv-titans-1586865/
... View more