Combined with a healthy diet, any physical activity can help with weight loss. However the key is to ensure your diet is in order first. Eating whole foods, minimising sugar and refined carbohydrates and a calroie deficit are all necessary for good health. There are plenty of questions on this site that cover dietary changes for weight loss that are worth reading.
There are lots of reasons to workout, however exercise without a change in diet rarely leads directly to weight loss.
However, tennis has a lot of other good aspects. It requires flexibility, hand eye coordination and the ability to change direction. It emphasises quick explosive bursts of energy, not unlike High Intensity Interval Trainning. But your assertion that it doesn't require endurance is not true. Professional level tennis matches can last for hours, and even at the amateur level, even though you have periods where you are standing still your body will still be in a heightened state both attempting to recover from the last burst and getting ready for the next one.