I'm looking at buying a baitcaster but before I do I want to know why alot of people have this type of reel? Whats the advantage over a regular spinning reel. I want to know why people like them so much even since their hard to master.

They really aren't all that hard to learn. A couple of hours in the backyard and you'll be ready to give it a shot at the lake. Yes, you'll backlash and curse, but you'll get better over time.

The biggest benefit I see over spinning reels is that your line doesn't twist as much, which means it doesn't break as much. Also much easier to control the distance of your cast or pitch using your thumb.

That said, plenty of good fisherman choose to only use spinning gear and do just fine.

You can fish heavier lures with higher pound test line.  My accuracy is significantly better with a baitcaster and my thumb.  I can control where and how my lure lands better with a baitcaster.