"Integrated LED" refers to the configuration of the LED light source. With this type, the LED chips are mounted on circuit boards that are directly attached to (or integrated into) the fixture housing. This type does not require a socket since the LEDs are not enclosed in a lamp or bulb.
The other configuration is the "lamp-ready" type. This is the familiar arrangement where the fixture contains a socket into which the lamp or bulb is inserted.
One advantage of the integrated type is that there is more space for the LEDs and circuit components to be mounted into the fixture. LED lamps typically have a very small space that limits the types and functions of components.
Another advantage of integrated fixtures is that the heat generated by the LEDs and other components is more efficiently transferred away from these heat-sensitive components. LED lamps only have their pin connectors and surrounding air to conduct the heat - a far less efficient method. This is less of an issue with newer more heat-stable LEDs. They still exhibit extremely long lives.
Integrated fixtures also have the advantage of interchangeable optics. After installation, occaisions arise when the designer wishes to change the beam angle. This may come up when plant material grows. With the integrated AMP® One fixtures, changing the beam spread can be accomplished with minimal cost and time by simply changing the optical element. With lamp-ready fixtures, the entire lamp needs to be changed.