I think most of us don't. I also don't like the reasoning - extra maneuverability? More efficiency? Without any real explanation.
You have to put on your engineering mentality a bit to understand why they say that.
In the current day, Synchronous Autonomous Flying can already be done via computer.
Just see all the Modern Day Drone Light Shows where it replaced FireWorks.
That automatically takes care of the floating seperate sections.
Automatic Wireless Communication via Computers lets all sections work in tandem like Synchronized Ballet Swimming.
Now imagine how effortlessly & refined several centuries of improvement will be done to the code base & knowledge base to have multiple independent sections fly together.
Less Mass for a vehicle & each individual section = easier to maneuver at STL speeds.
No need for Pylons or Necks, everything can move on it's own and has less mass to move to begin with since they are seperate sections.
There doesn't need to be extra reinforcement for the Pylons & Necks as well in the structural members of all sections.
That means each section doesn't need as large of a Anti-Grav Drive or Impulse Deck to move at similar speeds as a traditional Single-Piece Connected Ship.
That also leads to less energy consumption since you can use a "Right-Sized" Gravimetric Drive & Impulse Deck for your independent sections to meet specified performance design.
We saw with the 24th Century Defiant-Class that Warp Cores were getting smaller & remained ridiculously powerful.
Now imagine several centuries of refinement of compacting the powerful Warp Cores.
Place a seperate Warp Core in each of the Floating sections along with Impulse Drive & Batteries.
Each Unit can be it's own mini StarShip section as need be.
Individual Flying Sections allow redundancy in battle & makes each individual unit a "Hot Swappable" part in real time.
If you loose a Warp Nacelle, you can ask for HQ to send you a replacement w/o getting towed back to StarBase for Repairs and/or RetroFits.
Now you have lower individual ship sections Surface Area for Shields to Cover.
The independent Surface Area for each individual unit is smaller, ergo you can have Denser Shields for each Floating Section.
Or have all of the floating sections work together to have one large Ovaloid Shield Bubble.
Take your pick.
Smaller Surface Area = Less Power needed for Skin Shields or more power for less Surface Area.
You get Denser Shields by having more Shield Particles covering a Smaller 3D Surface Area.
Or you can have 1 Big Shield Bubble powered by multiple Shield Generators in concert from each floating section of the ship.
Either way, Shields will be improved by the configuration of each individual section working in tandem.