Before looking at speakers versus soundboard you should check what outputs you have on the telly; it's no good buying any sort of additional audio device without knowing for sure that you can connect it to the TV.
The most common connection is Optical output. A headphone jack is probably second most common. Very few TVs have a dedicated audio out on red and white phono any more. If you have those sockets on the TV just check very carefully, they're probably marked "Audio IN" and that's not the same thing at all. I haven't seen any consumer TVs with speaker outputs in nearly a decade, so buying Hi-Fi speakers without some kind of amplifier to go with then is a complete waste of time.