An ordinary old computer works just fine for the task.
We prefer to be able to watch on our TV. The picture is better, it is less strain on the eyes and it is just more relaxing.
If you mean that the computer can be hooked directly to the TV w/o the intervening streaming device, we looked into that. We aren’t techies and it seemed to need the computer still hooked up to both the TV and the modem via a cable, so instead of a dedicated computer, we opted for the $100 Roku.
Also, w/Roku we have access to a lot of different channels without downloading all sorts of plug-ins. I had attempted various sites using plug-ins and many of them would not play on my browsers.
Roku is great for us geezers, IMO. Very simple plug and play and less clutter. Roku II has been just about glitch free. In fact, last night we seemed to have no trouble with one of us online and the other watching TV. It may just have been that fewer folks in our area were using bandwidth, but it was quite nice.