TVs aren't expensive anymore. He says he got a TCL from Costco. I just checked their website and the 43" model costs $239.
No platform has more and better apps than Roku. A box is a closed platform just like Roku. Any of the things you're worried about are just as likely with a separate piece of hardware running smart TV software as with the software running on the TV itself.
Roku is the most open platform out there. It’s easy enough to write and use “private channels” using their SDK. Roku doesn’t have to approve a private channel.
No platform has more and better apps than Roku. A box is a closed platform just like Roku. Any of the things you're worried about are just as likely with a separate piece of hardware running smart TV software as with the software running on the TV itself.