Grumpy_Mike:
The Pi is not real time it is Linux.
There is nothing you can do with a Pi that you can't do with an arduino and laptop. But there is plenty you can do with an arduino and laptop that you can't do with a Pi.
However it is much cheaper than a laptop and Arduino.
I wish you answered sooner lol. Since its cheap I bought it, im curious what it is. Now i can answer my question, its just a cheap computer, i read somewhere thats its good for learning computer language, but only for people who doesnt have laptop or pc.
Who doesnt have computer nowadays lol. Im into arduino so im also not interested in rasp gpio.
You can attach it to a project but i heared its not also designed to be turned on forever. I dont hate it but I dont need it 
A complete PI is also bigger than my macbook air.
I bought a book " programming rasp pi, getting started with python" , I found out that i dont even need A PI for the book lol.