What is there to tinker? Using the connector on the back? As you pointed out, you get that on the cheaper option.
The mini PCs sold everywhere these days use standard Linux with over the counter components by Intel and AMD that are documented to death. They have the memory, faster CPU, fast storage, multiple HDMI outs, power switches etc. They run Windows if that's your thing. You can actually use them as your main computer if you are a teenager or light user.
This is far from the British computers that theoretically inspired the foundation. Even the cheaper 500 isn't such a great value for real world computer education. I bet more adult hobbyists like me use them than actual children.