The mix seems quite insensitive to shock and friction but its complete safety profile remains to be investigated. The loose powder burns very fast but not as fast as benzoate whistle mix.
Source: AFN #64, Jan. 1987, Dave Bleser Small pumped stars (3/16″x5/8″) were made using 1% nitrocellulose binder in acetone. Their burning rate was measured on the ground to be 3.8 mm/sec which is quite fast, as normal color compositions burn around 1.5-2/5 mm/sec. The small stars burned with a beautiful blue large flame with no red tip and darted around the pan they were burning in. Ed.: I used dextrin at +5% to bind these with no issues.