Rather than assume you're an idiot, let's assume I'm an idiot and I'll ask you some easy questions, and maybe the answers will guide us somewhere.
Is there a difference between investment and speculation? If so, what is it?
What is a "risk"? Are all risks of the same nature? If not, can we identify broad categories?
How can we measure risk? Is the measure absolute or relative? If the latter, what is it relative to? Does it matter which category of risk we are dealing with? If we can't figure out a measure, can we at least figure out some deirable features of a measure?
What does it mean to get reward for a risk? If there are different categories of risk, are there different categories of reward? If not, can we map rewards to all risks? If not, why not?
Does the reward affect the risk measure?
Where do returns come from? Does it matter? Is this related to the risks?
Assuming we can answer all that, can we relate the difference between speculation and investment to the categories of risk? What about the sources of reward?
What are the categories of risk involved in buying bitcoins? Does that tell us anything about it as investment or speculation?
I apologise, that's a lot of questions!