Convert or not convert? For me it depends on a clan I am playing..
Mori-never.. Uesugy and Hojo –no real need.. All other –convert immediately..
Main benefit-you not depends on good harvests so much…Very easy you can make trade and cathedral income equal yours farm ones, dubling totals. When in bad year will be only 12.5 % drop in total money.
And I never been fond of monks, if not play Mori-there are too expensive..