To be fair, you asked "wtf is
the point of a b-side?" not "what
is a b-side?". Do you notice the difference in how the 2 questions are understood?
Asking "what is the point" of something is different than asking "what is" something. In the first question you are asking why something is happening and in the second question you would have been asking what that something is.
Your original question asked why, not what. "What is the point" is understood as "why do it?" not "what is it?"