The difference is that with investing, you have a reasonable indication where your investment will end up in the future. Chances are, in 10 years Walmart is still going to be profitable and continue to pay out dividends. There's no telling what will happen to Bitcoin in the next week, let alone the next year, so it's a gamble to put your money in Bitcoin.
Do you not see how you are contradicting yourself?
"Chances are" alone, is an assumption. How is that any different from your speculation on Bitcoin. The only difference is longevity of the window period, otherwise it's the same principle.
There is always going to be some degree of uncertainty with any action. Just because a meteor can fall on your head if you walk outside doesn't make it a gamble to do so. There's a fine line between investing and gambling, but the extreme ends of the spectrum should be obvious.
I'd argue that the difference between investing and gambling is that gambling has known negative expected value, whereas investing is uncertain. If it is not known that the outcome of a gamble has negative EV, then a reasonable case can be made that it is an investment.
