Sure, there's a reason for it.

Symmetry is one.

Frames see stresses on raising day that they will never see again (hopefully). Some folks just stick braces in everywhere, figuring that more than a few of them will be left out or cut out by the people who actually have to use the building, and are not interested in having a lobotomy every time they use the stairs.

There is also the common engineering phenomena known variously as "I never met a brace I didn't like", or as "Floor to ceiling x-braces right across these windows."

Timber frames, even when poorly designed, usually include sufficient redundancy to permit the removal of a brace or two without catastrophic result. Of couse, in these litigious times, you didn't hear this from me.