Rooting is a confusing term to Android newcomers, but it’s really simple: It’s gaining administrative rights, just like you have on a Windows PC. It’s nothing particularly nefarious.
The difference is that it’s not quite as straightforward with Android.
I understand the decision: Google didn’t want the potential liability of hundreds of millions of tiny Linux boxes running as root, but also didn’t want to create a totally closed ecosystem, so they made it difficult, but not impossible.
The way to go about gaining root access varies from device to device. There are some “super one click” packages that will root a lot of devices, but not all of them, of course. The best thing to do is just search on whatever device you have and the word “root” to find out how to gain root access. Anti-climactic, I know.
But the benefits are many. Most Android antivirus programs will also give you a firewall–if you’re running as root. Having a firewall on your phone doesn’t make it invincible, but it makes it much more resistant to attack over the network. It’s a good thing.
Once the phone is rooted, when a program requests root access, you get a prompt, much like in modern versions of Windows. You can then allow or deny the app that permission, and have it remember your decision.
If you’re in the habit of modifying your hosts file on Windows systems, you have to root an Android to do the same. There can be benefits to that, too.
You can install a custom recovery, which then opens the door to custom ROM installs. Think of custom ROMs like Linux distributions. They all provide pretty much the same base functionality, but each has its own specialty, and you may very well take more of a liking to one than the others.
And you can give up root access too. Most of the tools that will root your device will also un-root it for you as well. Many corporate policies don’t allow rooted devices on their network, or won’t let you install their mail client to a rooted device. So you can root your device, make the changes you want, then unroot it so you can use the device at work. You’ll lose the firewall functionality, but the other changes you made will remain.