Please show me a dirt simple pc interface then for hobbyists. The pi has one. So does arduino
Right, for LED blinking etc. it is not easy with a PC, if you don't use an Arduino. But Eben Upton wrote, that it makes easier to learn programming, and this is wrong. I've just installed the current Raspbian distribution for my Raspberry Pi and if you manage to start X, you can see the following programming related programs:
- Scratch, a really nice Lego-like programming environment:
http://scratch.mit.edu , but which you can just run in your browser on PC or Mac, too, but which is available as an offline version for Windows, Mac and Linux
- Idle, a Python IDE, available for Windows, Linux and Mac, too
- Python Games, a list of games written with PyGame, which you can click
- Squeak (hidden in the start menu), as described before, which is also available for Windows and Mac.
Idle is a nice entry level IDE, but of course, it is just a Debian installation, so you could install KDevelop or any other program you like. I really don't see how it is easier to program with the Raspi than with a PC.
When I started with the C64 as a kid, I was not interested in external hardware (later a bit, when I developed a simple ADC for the user-port to sample music for my demos). Some kids might be interesting in blinking LEDs, but I doubt it, in the era of smartphones.
But writing your own game might be still interesting and then later maybe they are interested in hardware, too. For this combination, programming and external hardware, the Raspi is better than a PC, but the same is true for an Arduino, at beginners level. It is even more limited, because no ADC input or DAC output, so for many things which you can do with an Arduino, you'll need extra hardware for the Raspi.