To be clear, I was not suggesting that a BP/W with a specific wing and plate is flexible to all dive situations. But if you wanted to change one part of a BP/W, you can do that without searching and hoping someone makes a complete BC with all the things you liked about your current BC but with the one change you wanted to make. Understanding that the wing is a big part/component that is expensive and likely impractical to customize internally once you’ve picked it, you would need to buy a new wing.
(Thou some small doubles wings may be serviceable but not near optimal for both singles and modest doubles, e.g., DivRite Rec wing, though not really recommended for singles. And when I was researching small doubles, some singles wings were recommended as compatible, some of the less tailored ones in shape. So one wing can cover a wide range.)
The easy and more frequent use of flexibility is what you put where on it. Particularly trim weights can be put on any of the straps or even the plate top edge. That is not as easy, in a clean and tidy manner, with most sewn together BCs that I have seen.
ETA: The buddy commando does not look any different from other sewn together BCs in this respect.