.....Burn for a longer duration, this would require 2 of the stuff having contact, OXID has to touch any of the elements it can ignite...it makes things a bit more complicated...
...Besides, if your having problems igniting stuff, just put ELEC, one on each side on the end where the fuel will come out and SPRK.
Oxidizers causes things to burn way faster, because they provide more oxygen than just the one in the air.
An example would be gunpowder. Without the oxidizer ( Potassium Nitrate ), gunpowder is just charcoal and sulfur, two substances that burn quite slowly. The potassium nitrate makes the reaction happen much faster.