There are many reasons to invest in real estate. First and foremost is "independence".

You can do it as a side activity to augment your income, or you can become a full-time, professional investor. It can be as small as you want, with 1 or 2 units, or you can grow to apartment buildings, and build your real estate empire.

It's up to you once you get comfortable with it, and what your needs and dreams are. Either way, it's your business!