Here's my take on why the author of the seforim Bilvavi Mishkan Evneh, started off anonymously, from a Hashgacha Pratis perspective. If everyone knew who the author was at the very beginning when the seforim first began to come out about 3 years ago, then I believe that it would have been an impediment to the wide ranging acceptance the seforim have had. As it is, during his visit to the Eastern United States, Rav Shwartz spoke to Litvish Yeshivos, Kollelim and Baalabatim, Sephardi Yeshivos and Kollelim and Baalabatim, a Chassidishe kollel, a modern orthodox yeshiva, and to numerous FFB and BT Baalabatim from all backgrounds.
I believe that some would not have given the seforim a chance, if they knew who the author was at the beginning. Many might have said that the author is too young. Others would have said that since he's not coming from a Chassidisheh background, or their particular Chassidishe background, it's not for them. And Sephardim might dismiss it because it's from an Ashkenazi Rav.
As it was, no one knew who the author was or what his background or "denominational affiliation" was. Therefore, the seforim were judged based on their content, not the group affiliation of the author. Since the seforim draw light from many different paths in avodas Hashem and Torah, everyone saw the teachings of their own group in his writings. Everyone figured, "Look at what he says here, he's a Breslover!" "He's Sephardi!" "He's a Litvak!" "He's a Lubavitcher!" Since everyone saw the amazing clarity and direction that the seforim provided in focusing an individual's avodah in this world, they accepted it for its content, notwithstanding the mysterious identity of its author. Before you know it, the seforim were being studied in Litvish yeshivos, Chassidishe communities, Sephardi Shuls, and modern orthodox enclaves.
In the past 3 months, as the author's identity has become known, people are finding out that the author has a certain background, but that he draws his teachings from a unification of many different sources. This is why everyone was able to see their own mesorah in his teachings. Once they were learning the seforim and it had become accepted in their communities, people weren't going to stop learning them, simply because of some difference between the author's background and their own. It is for this exceedingly great advantage that I believe much good has come from the author starting out anonymously.
I told Rav Weinberger this theory of mine in the conversation that I wrote about before. He very much liked the idea, and in a subsequent conversation, told me that he told over my thought to Rav Shwartz himself!
We should all be zocheh to internalize the message of consciousness of Hashem at all times, that Rav Shwartz teaches about in his seforim!
(Picture courtesy of Yoram Raanan)