Online earning from home is useful or just a waste of time?

As there are thousands of ways to earn online but with this there are a lot of problems like the major one is the site which we opt to work is either legit or scam? Not only that but about how much we can earn at the end of month and many more queries and concerns with this which usually results in giving up to earn through this method. But on the other hand, there are people who earns thousands of dollars from their home's comfort zone by giving two to three hours working online. So what you guys think, working online is a very useful method or there are better options than that?