The thing is, it all depends on you. If you want to be reached by more people, then it is highly recommended that you have one. Also, most of the marketing people have theirs, and for you to be able to compete, then you should have one.
Some of the benefits of having your own website are the following:
1. You can let the people know that you are serious with what you are promoting.
2. You can provide your visitors the information about your brand.
3. If you successfully gained a good rank in search engine results, then you will gain more.
You can use social media as your platform, but it is definitely better if you have your own site. With a good website, and an effective social media marketing, your traffic will be increased and more opportunities are coming your way.