I had a short conversation with M0N many moons ago about balanced audio for speakers…it didn’t really go anywhere aside from his comment of it being ’ complicated’.
so, using plain laymen English, not overly technical terms that run circles around our head, can someone(s) talk about the pros / cons of having a balanced chain for a speaker system? how are speakers ‘balanced’? and lastly, also importantly, how affordable is deploying a 2.1 balanced setup? tower and bookshelf?
From my understanding the whole point of balanced source gear for speaker setups was to reject the most noise possible over a long distance. After that I’m not sure if balanced really plays a big roll.
Before the Amplifier: Same as with any audio setup (recording/mixing/hifi), you have higher noise immunity and less ground related issues.
After the Amplifier: Power levels are so high and sensitivity (compared to the “active” components) so low, unless you have an accidental transformer around a power cable or live next to a radio broadcast tower, it does not matter. You would likely have a hard time to measure this, honestly…
Same as headphones: They are NOT balanced in the electrical sense.
When you go with PA gear, likely the same as a Mid-Fi setup.
When you go HiFi, you are paying through the nose for balanced (for whatever reason…)
‘PA gear’? that does that break down into for full words? 
Public Address (System), the equipment you see at concerts, in stadiums, town fairs, etc.
so realistically, unless you have money to blow, it doesn’t really have any real world value / impact but for a few scenarios involving interference?
It has value in reducing the impact of messy cabling, a problem you can solve at home by putting 10% more effort into your setup.