Absolute encoders have a non-volatile memory where position is not lost when power is removed. Continuous read is not required. Typically have high resolution 16 bit. Typically used when safety is a concern. Single and multi-turn revolution options. Applications: robotics, automated gates, camera gimbal and factory automation.
Incremental encoders position pulses are counted when power is applied position is not stored. Typically lower cost and high noise immunity. Good for simple pulse counting or frequency monitoring for speed, direction or position. Applications: ball screw positioning, conveying, cut-to-length, filling, and food and beverage for example.
I hope this helps.