Interesting video on the kampilan

"Visayans were very close to cultural spots like those of what would become Indonesia.... Majapahit and other Sultanate and Rajahnate cultures in trade and the Austronesians of the would be Indo-Malaysian archipelago were the ones who invented the Kampilan sword family from which Moros literally derived their swords. There were back and forth migrations of Austronesians, it is unrealistic to say the least that non-Muslim Filipinos never used Kampilans. They obviously did, including the Lusungs (who were of Luzon origin ethnically) who were employed as mercenaries and fought in Thailand also obviously did.

Religion is irrelevant, as most Filipinos of Austronesian origin are all ethnically the same, well, small exception for Igorots for being far purer Austronesian."

Actually, the blade that swells towards the tip as seen on the kampilan along a few other examples, dates back to India or Indo-European as that concept was what spread towards Nepal and south east asia maritime and mainland. To give the southeast Asians in Indonesia/Malaysia the credit without acknowledging what people they learned it from is another way to stab oneself in the foot. 

I agree with your point on the spear. I'm not sure if I posted it here or on the previous forum site but, out of most weapons the spear is seen as the best weapon on the field even in a pact island like the Philippines. Even for the moros, I've been told by one that practices silat on how spears have always been the primary to-go weapon while the sword or knife is seen as purely a side arm. The kris and barong are maybe preferred on special cases when a juramentado attack happens. 

I agree that spears are better than swords, and that's why most tribes used spears as compared to swords.  As you mentioned they are a lot cheaper and require less metal for construction which obviously is an expensive material.  Spears can be made from a variety of materials that are readily available, and can be made quicker than swords.  Spears don't even require a metal tip if metal can't be found or is too expensive.  

Spears are also easier to use in my opinion, require less training, and are generally more safer for the wielder as compared to swords.  You can easily hit yourself with the blade of a sword.  Spears are also lighter, therefore easier and faster to use, and lead to less exhaustion.  

Spears can be thrown.  Swords usually are not thrown as they are not good projectiles.

Spears provide distance that swords cannot effectively do.   This is important at individual fights but also group fights especially formations as shown in that video that was posted.  Had the spear wielders had more training and holding their formation especially a formation with two or three lines of soldiers one behind the other, then we could see how effective the spear is in battle.  

As mentioned earlier spears provide distance, but they are also have quick movements (especially quick back and forth movements) that are quicker than the side swings of swords especially the swords that were used in the video.  The spear is a hard weapon to fight against with a sword, because a spear wielder can attack, retract its spear and attack again very quickly.  Moreover, if a swordsman attempts to close the distance and manages to pass the spear, the spear wielder can still retract the spear (and even walk backwards) to attack the swordsman at the closer distance.  

Spears resemble the fencing foil.  The foil has been proven to be very effective against most swords due to its speed and ease of use (short quick movements of the arm and wrist).  The main weakness of the foil is that it's not effective against armor.  The spear can be effective against armor especially if it's a heavier spear with a strong and sharp spearhead.   

Spears are also versatile.  They can be used for hunting a variety of animals on land, trees, or in the water.  A soldier would want such a survival tool if the situation called for it.