B.Net ninja patches are fine and dont really mean much, they arent the actual game so HB doesnt need changes as HB doesnt attach to the B.Net only the wow.exe. (they are seperate programs)
Updates can be little things like ive seen a few times just grammar and spelling alterations, adding new advertising general update of content or general processing and efficiency improvements as it does use alot of cpu for a desktop app. They constantly develop this app so im not surprised (ever looked at how long the list of possible error messages there are?)
All the B.net does is allow you to access all your games from one place its litrally just somthing that holds paths to the games executable and runs updates.
Think of it like 'google play store' u download games from it, you 'can' open them from it and you update from there somtimes, but the game and playstore are different programs. on a very loose connection B.net and the games are like that (just owned by the same company).
Steam is another example of this, you can install the game and run directly from its executable but steam offers you a handy place to run your games from and update easily. get where im going with the examples?
No need to worry about b.net updates
You can run wow from the 32bit straight up i never use the bnet anyway its just unnecessary to use every time, just use to update the game when needed.