Understanding the local culture and language is an essential part of studying a country's history. Does this mean that the works of local scholars, generally speaking, deserves more attention than those of foreign scholars?
I do not know much about history of Philippines, but usually it is better to have several different perspectives. National historians are frequently biased, but some foreign historians may be biased as well. The best books that I read about recent history of Russia, for example are written by British and US historians.
And I would be delighted to read a history of Greek-Persian wars written by a (contemporary) Persian historian. Unfortunately it does not exist.
In my experience, as a general rule, local historians tend to be superior to foreign historians. The reasons for this are that local historians generally tend to be a lot more detailed about their local history and they often have access to local data sources which are unavailable to a foreign scholar. Whenever I go to Europe I am always amazed by how incredibly detailed some local histories are. For example, I went to the ancient city of Korcula and it is filled with archives and documents about its history which can only be found there.
Of course, there are plenty of exceptions, but in my opinion you should always begin with the local histories as a starting point.