Cardio is used within programmes as a fat loss tool, it doesn’t necessarily burn fat, but it can help create the calorie deficit required to lose body fat.
But what’s better? Low intensity or high intensity?
Low Intensity
Low intensity training is easier, but takes longer, which I great if you have enough time, can’t put too much pressure through your joints or are recovering from injuries. Low intensity is great for people wanting to just feel fitter, move more and be a little more active through life.
High Intensity
High intensity is obviously the opposite, you can burn the same number of calories at a faster rate, but will put a lot more pressure through the joints. Usually incorporating a timed factor and more impactful exercise selection, HIIT tends to be a little more advanced then LISS. Because of this, high intensity training lends itself to developing energy systems for sports that require repeated sprints or high intense periods (e.g. Team sports, athletics, sprints etc).
Conclusion
Is one better than the other? No, they both have a place, and both burn calorie, improve health and cardiovascular systems. Choose whichever suits your lifestyle at that time.