Yes, the newly launched rain tracking satellite will be beneficial to humanity, because the more information we have the better it will be. Tracking rain helps people make better choices about their events. People can decide whether to cancel or move the event indoor. Meteorologists can study rain patters and develop new models based on the satellite data.
Precipitation is necessary on planet earth. The prediction satellite has more uses than to remind us when to wear a raincoat or bring an umbrella. The planet still produces food. At the most basic level of agriculture, knowing when to expect rain could save money on irrigation options, and reduce crop loss due to drought.
This question is one that has been around for quite some time and is not easily answered. There are groups on both sides of the issue that will insist that they are right and they will not budge regarding their opinions. Both sides have quality arguments and they both need to be open minded.
Any way we can keep an accurate forecast of the weather would be beneficial for humanity. It could help us with our crops, show us when to conserve water, and even help with weather related safety issues. Technology like this is a great thing, and I am glad to see it has launched.
Of course rain tracking satellites are beneficial to humanity. Knowing where the water goes on a global scale will help us to devise better ways of capturing that runoff for use. It could lead to revolutions in where, when and how we plant crops. It could bring water to countries who have very little of it.