David, I agree with you that the keris is not designed for fighting, though to certain degree, is worthy enough.
In Malay keris culture, keris is a part of a complete dress and a (side) weapon. Having talismanic properties in the keris is a bonus
Also, no Malay would use warangan to stain or bring out the pamor of a keris. The use lime or pine apple juice will do just fine.