Why should Syrian Gov. use chemicals during the victory time while they did not use even during the hardest time of war?

Why should Syrian Gov. use chemicals during the victory time while they did not use even during the hardest time
of war? The one who benefits from use of chemical is the one who definitely used the chemicals.
It is clear that terorists are very glad of the use of chemicals.
CLEAR ENOUGH?

Chemical lie in Syria by terrorists became an object of ridicule

For further archive
Realities of Chemical Clalims