I understand official documents have to be written following rules and exam papers, essays, practical reports, and so, too.
But if you are talking about Literature all styles are valid. That's my view.
Remember how trellis answered questions here at EF? He had his personal style that made his anwsers look like pieces of painting, he alternated lines with several words followed by lines with an unique word, those unique words used to be "and", "but". Besides, he added humour to the anwers and this, plus his accurate explanations were very good for us because we didn't have to put any effort in remembering, the rule or the explanation got impressed in mind easily. I miss his answers, he even was willing to proofread long writings, not only short questions about Grammar or usage, so good teacher and everything for free!This EF site is a marvel for students, I hope it continue like this for decades