Longer rods are definitely a big help when floatfishing on rivers. I've never owned one of the super-light Acolytes, but I've always found the trade-off - a little extra weight against increased ease and control - worthwhile for any of the models, such as Preston, Tri-cast, Daiwa, thatI have owned.
I use 15' rods - usually the Carbonactive 15/17' ( I lost track of the 2' section years ago, and don't care if it ever comes to light) - a lot on stillwater. And not because they're deep; I use sliders for that. I use them for the sheer pleasure of fishing with a long rod and pin. The extra length gives you that bit more line to play with and a bit more range if you want it - with very light floats taking maybe a couple of no 6's or 4's, you don't want to be messing about with loop casts and you can't cast such floats off the reel. The set up gives you some of the advantages of pole fishing, with running line flexibility.
If the water holds a good mix of fish, the bigger ones are great fun to play on the pin. Many advocates of shorter rods - they tend to be anglers who fish commercials for carp - claim it's an advantage that the fish come to the surface closer to the bank and are easier to net. That's true if your water has banks like a swimming pool. If your banks have reed beds, weed and rough margins and other real-world features,, a long rod is useful for keeping fish out of possible snags.
One way and another, I wouldn't be without a few rods over 13'.