I was first an investor, then a real estate agent in that order. Regarding online or in person, it definitely depends on your learning style. That's why both are offered. I went the online route because I couldn't take days away to do it in person.
As for whether or not you should get a license, it really depends on a few things. First and foremost, real estate sales is a full-time job, and the fees associated with it can be hefty if you are only dabbling or doing a handful of deals. You'll need to hang your license under a broker, and pay them either a percentage of your commissions, desk fees, etc depending on how they do it. You'll also have MLS and other licensing fees, continuing ed. If you are only getting the license for investing purposes, I would say its not worth it from a financial perspective.
Also, once you are an agent, listing your own properties can be tricky as you are held to different standards and responsible for other things that don't affect you as a non-licensed person selling property. Yes, your license gets you access into properties, and the ability to speak with agents directly about information you might have trouble getting otherwise. This does allow you to be "first in the door" on some deals, either for you or investor clients, but deals on properties on MLS are harder to come by than you might think.
Think it through, otherwise you could end up jumping in, spending a lot of money, and then realizing its not a good fit for your goals.