Shattariyah in Southeast Asia

Mrs. Prof. Yumi Sugihara sent recently two books to Utrecht. One is the fine translations of the Ghatotkacasraya, the story of Gatotkaca in Old javanese, translated by Stuart Robson. I will reflect later about this book.
First a little about the book by Oman Fahurrahman (born Kuningan 1969, studied in Jakarta, UIN, did research in Aceh, Germany and Tokyo) on the chain of transmitters of the Shattariya brotherhood on Southeast Asia. In description about him he is qualified as someone 'crazy about manuscripts'.
In the book Shattariyah Silsilah in Aceh, Java and the Lanao area of Mindanao, (Tokyo University of Foreign Studies; 2016) he shows himself to be addicted to manuscripts and especially to the chain of transmitters of the tariqa. Not the content of doctrine or practices, but the chain of leaders is always given attention to here.
This reminded me of the former Utrecht Professor of Islam, Fred de jong, who studied brotherhoods in Egypt in the late 19th century: it was always about leaders, silsilah, chains of authority.

This reminded me of the difference in study of shari'a by Muslim and Western scholars. Hadith, the basis of many shari'a rulings, is divided in two aspects: the matn or centre, body, content of the rulins and the isnad or chain of transmitters. While many western scholars (from Goldziher to Schacht) do not give much attention to isnad, the Muslim scholars put the isnad on the first place.
There is a naughty story in the Kitab al-aghani, the classic Arab collection of poetry, songs and short stories. A group enters a boat for a trip from Baghdad to Basra. A Jew has taken his bag for wine and before sunset he takes the bag, fills a glass and says to the public: 'This morning I sent my most trusted slave to a wineshop and he brought me again of the fines wine in Baghdad. Hé, Muslim, would you like to taste my wine?' The Muslim answers: 'Well, let me try your drink.' The Jew repeats: 'You are a Muslim. How can you drink from my wine?' 'Well, is the Muslim's answer: how assures me that this is wine? I hear it from a Jew, who sent his slave to a wine-seller. Well, nice stuff you gave me here!'
Is the emphasis of Oman Fathurrahman on the silsilah also similar to the general tradition of giving attention to isnad and not to matn? I found a well written and good book, but resented that there is no development in social status of adherents, not development of doctrine and practices here: just the chains of leadership.