Just a recap, why would anyone use a peracid to make an epoxide if you could just use hydrogen peroxide? To my knowledge, that reaction doesn't work. You can use hydrogen peroxide and a carboxylic acid to make a peracid or just start with a peracid to make an epoxide. There is also a Payne epoxidation in which hydrogen peroxide is used with a nitrile to make an iminoperacid. So, my comment was, the JACS paper did not look like a new and novel way to make an epoxide. Furthermore, since JACS is noted to be very particular about the merit of their papers, I just thought at first blush, how did this make it into JACS? I didn't bother to read the paper, I should wondered how one could make an epoxide with hydrogen peroxide.
By the way, why this paper got published in JACS does nothing to answering the posters question.