Ligers are giants because of "hybrid vigor", in which they gain the strengths and attributes of both parents. Ligers live long, healthy lives, are very smart and show great resistance to illness and disease.
Ligers are incredibly social animals and are comfortable living with both lions and tigers. They also display genuine affection for their human handler's and trainers.
Contrary to popular belief, ligers are not a "man-made" creation. Similar to pizzlies (polar bear / grizzly bear hybrids) and wolphins (whale / dolphin hybrids), ligers have existed in the wild for thousands of years. Due to the recent decline in both lion and tiger populations, however, their territories no longer overlap.
While some people do not consider ligers as "zoologically significant", their true importance is in getting people's attention and helping to convey the importance of global biodiversity and conservation. Obviously it works. . . . . after all, you are watching the video and reading this statement.