Flame-Resistant - Wadding in NOT ordinary tissue paper. It is treated with a special chemical to make it resistant to fire, so it is hard to burn. When exposed to a flame, it chars instead of burning. This feature is what protects the parachute from melting.
Stiff and springy - Because it is springy, it fills the tube easily, preventing buring particles from slipping past and hitting the parachute.
Cost Effective - It is cheap insurance to improve the odds that the parachute opens fully and the model lands softly. Plus, you'll get 100 sheets of wadding, enough for about 30 flights.