If I understand your question, Eddie, you are asking about the advantage of writing a thesis as if it were an extensive article worthy of being published in a prestigious research journal. In the Humanities, save in exceptional circumstances, this is precisely what a thesis should be. It should start out from an original premise, expose the criticism for and against, then make an orderly chapter-by-chapter case in favor. In scholarly articles, we do just that, though in a shorter version.
It will be briefer than otherwise, and would avoid many unnecessary details. This would enhance its readability. It will also involve less hassles in making publishable paper/s out of it. The examiner/s who is/are used to reviewing papers for that journal, may find it more interesting to evaluate the thesis. But some details may have to be brought in the appendix, as the examiner might like to know some details that may not be required in a journal format.
I guess, it depends on the format of a particular research journal. Some might have even more demanding requirements than schools. In that case, it would more likely a disadvantage. Otherwise, the only advantage of such adoption is the lack of need for substantial preparation of a paper for submission to that particular journal. However, what, if you want to submit it to another outlet? This is where advantages end. In a grand scheme of things, I think it's not that important, as the essence is what matters, not the form.
Adoption of Formats limits Innovation and creative flow and expression of an Output. A framework can be suggested that the thesis should mandatory cover certain areas, but should not force that only such should be limited with.
The researcher should have the freedom to describe and take pride in picturing the research output, which is relatively immortal and seed for further research.
Part of the learning process a student undergoes in postgraduate srudies is that of presenting work in a format acceptable to the academic community. By asking the student to use the format of a well known journal, they will learn how to adhere to rules of publication. I believe a dissertaion should have an introduction and conclusion on either side of all the "publications" and it is here that the student should be allowed to be more creative and individualistic.
in Brazil, some Universities changed your own format to a paper format. A thesis can arrange 2 or 3 papers in the same document.
This happens because some students, after get their diplomas, they dont care anymore about publishing their jobs, and in this way, it is easier to send it to a Journal.
In Brazil, the number of published papers is much more important than dissertation or thesis approved.
A thesis manuscript often has a format in between that of a book (e.g. presentation of different chapters) and that of a scientific journal publication (e.g. presentation of new results). What fraction of the information presented in a thesis manuscript remains inaccessible to an international readership, and why?