It is also well to bear in mind that practicioners of contemporary wushu, which combined Chinese martial art technique with gymnastics, use VERY lightweight and highly flexible weapons. This is because their gymnastic routines would not allow them to handle the heavier, more traditional weapons.
The monks to which you refer actually use modern wushu-type weapons because much of what they do actually IS wushu as opposed to old, traditional forms. I have seen these "monks" in demonstration and it was several kliks below pitiful. They have no technique, their qigong demonstrations were no more than cheap tricks, and they are no more Buddhist monks than I'm a Catholic nun!
Goldendragon7 is quite correct about the spear's tassle. It is not used to distract; it was used to prevent blood from running down the shaft and making it slippery.
However, I will say that qi will NOT cause a "hard" blade to break.
A good blade, correctly made, is not brittle, nor is it overly-flexible (such as we see with wushu type blades). It has a strong blade which is very slightly flexible (in the case of the Jien; the double-edged straight sword). This flexibility has nothing to do with demonstrating qi; it has to do with making the blade strong enough to cut and thrust but flexible enough to withstand a blow from an opponent's weapon.
