Why wouldn't you want it to be a computer? Then it can be connected to your devices AND also do the job itself in a situation where it's awkward to connect to a device.
If already needs a computer in it to drive menus / modern display protocols. Having that computer be powerful enough to also decode content is barely an extra cost.
For the same reason I don't want a self-heating mug.
How about the abdysmal security Smart TVs either have right of the shelf or for certain after they are no longer kept up-to-date? I don't want to worry having my TV act either as botnet or spying device (many come with microphones and cameras nowadays). I rather purchase additional device that has decent security that I can attach to the TV if I need to.
> Why wouldn't you want it to be a computer?
Because I can then easily upgrade my computer without upgrading my TV.
> Why wouldn't you want it to be a computer?
The same reason I don't want anything else in my life to be a computer. A computer is one more component that can fail and take down the whole product. I want my computer to be a computer and that's it.
A rooted piece of trashy IOT is trashy IOT. It's an acquired taste, the excitement of putting a black box insecure linux device on the home network to add to your home infra admin duties.