Open source is particularly valuable when it allows you to use a device in a way not intended (or perhaps even envisioned) by the manufacturer.

But TVs are already about as hackable as you can get - They have a wide array of ports on the back that let you display any image/video you'd like. It's the polar opposite of something like a smartphone.

And it turns out most folks can hook into those ports just fine and get the results they want (hell, most tvs are directly controllable over hdmi these days).