Well, I wouldn't say a map with a single zone is just a smaller turf war. In turf war, all that matters is the end state. You can spend the entire round losing and then win in the last seconds with a couple well-placed splatters.

Splat zones are a "king of the hill" scenario, where your victory condition is for how long you managed to maintain control. In this mode, you could be "losing" when the game ends, but win the game because you spent more overall time during the match winning than you spent losing. Unlike a turf war, there is a point in splat zones when one team can no longer win, even if the match isn't over yet. They simply don't have enough time to overcome the point difference before the match is called.

With multiple zones to control, this can... change rather fundamentally, depending on how the game calculates point gains. Do you have to control a majority of the zones on the map (say, 2 of the map's 3 zones) to start scoring? Does each zone contribute its own scoring regardless of the state of other zones? If each zone contributes points independently, this actually causes ties to become possible, as both teams could be scoring simultaneously (which is fundamentally impossible on the 1-zone map we've seen in detail). But considering that the zones in the picture from the TC do not seem to be in symmetrical locations, I'm going to assume that maps will always have an odd number of zones, and you only score if you currently control more zones than your opponent does. This means the gameplay of having a single zone isn't fundamentally altered--only that you have more considerations to make in regards to where you attack opponents or defend your own holdings, as the entire team cannot concentrate on one location.

I could, of course, be wrong, but teams being able to score simultaneously would seem... directly at odds with the mechanics we see in the single-zone map, such as timer penalties for losing a zone.