Promoting events online is the most efficient way to market your events, you can easliy promote your event through social media and specialised platforms. It takes away all the hassle of registrations, so more people are turning to it as an easier option, which makes it easier to promote events locally or internationally through the internet.
The attendees can also use it to share their experiences which you can use to further promote your event organically. And when done properly you have almost no need to use any other ways like using fliers and newspaper ads.