Why does everyone split quotations with "He said", "she said", "I said", etc?

I’ve noticed that often in literature, the author will often split the quote into two parts, with the speech tag between them

• "It’s closed,” I said, “like I said yesterday.”

Why not put it after the sentence, or before it like:

• I said, "It’s closed, like I said yesterday".

Does anyone know why this is so common?