Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
My old Samsung smart tv doesn't have a Roku app available to install so I can't check this, but ... I suspect the Roku app you install on a non-Roku smart tv doesn't give you access to everything you can see via a Roku device, but I suspect it only gives you what Roku has available on its own THE ROKU CHANNEL, as that's the only Roku channel you can get on a desktop computer or via the Roku app on a smart phone.
Each channel's streaming rights are licensed separately for televisions, desktop computers, streaming devices, and mobile devices. Aside from Roku's own Roku Channel, you need to view the other Roku-available channels via a Roku device or tv that has Roku built in.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T