To start, let me give you a link that explain about jail breaking:
Jailbreaking Explained:
http://www.ipadforums.net/ipad-hacking/2838-jailbreak-explained-new-updated-2011-a.html
For me, personally, it's to make my use of my iPad easier and more of how I wish. I use a tweak called iKeywi to have a fifth row on my keyboard. So, not only do I have a fifth row, it's customizable so I can put my most often used characters on it (while I know a lot of people like having just numbers there). This speeds up my typing.
Then, I also run a tweak called SwipeSelection. With this, instead of having to press on the text to get the magnifying glass just so I can accurately place my cursor, I can merely "swipe" my fingers along the virtual keyboard and thus move the cursor back and forth.
Then, there is the tweak called SBSettings where I can have toggles to turn on/off my Bluetooth, WiFi, 3G connection - all with one tap of a toggle versus having to dig within the Settings app to find the appropriate place to do the action.
There are many, many other things that make using a jail broken iPad much better for me. Have a look at this thread to get an idea of what is available: Ultimate Tweak List:
http://www.ipadforums.net/showthread.php?t=25824
I am glad you are taking this time to get educated about jail breaking. May I suggest you also explain this to the individual(s) who told you jail breaking was to steal stuff. Share the knowledge!
Marilyn