Why we use Dual supply Emitter Bias in Transistor
With an BJT transistor in a linear circuit, you need to make the collector current (Ic) not depend on the HFE (used to be called Beta) of the transistor.
The usual method is to make some resistor on the emitter have a lot more voltage drop than the Vbe (Base to Emitter) of the transistor.
This can be done by having a positive and negative supply voltage and keeping the Base near zero volts.  Life, however, often doesn't give you two supply voltages. In that case, setting the base at some voltage part way between the positive and negative supplies is much easier than having to make a new power supply circuit. This is the two resistor voltage divider in many designs.
Sometimes you may find your self designing in a case where adding one more component will be objected to by management.  A resistor from the collector to the base of a BJT takes fewer parts than the voltage divider.
Sometimes the supply voltage you have is much too low for a normal design.  In this cases, you must get very creative about biasing of the transistors.