investment and speculation are two sides of the same coin (pardon the pun). all investment has risk. bitcoin speculation is a high risk investment. this may not be good for everyone but its an investment nonetheless.
Speculation is not investment. The difference is that investments pay dividends, and buy and hold is a viable strategy. A speculator is relying on appreciation to make flipping the asset pay off, and is screwed if they eventually need a greater fool and can't find one.
invest. "1. To commit (money or capital) in order to gain a financial return". nothing about dividends or buy and hold here. your definition seems very narrow by comparison.
I wouldn't take a definition seriously that failed to exclude lottery tickets.
Ever since Rich Dad, Poor Dad I've been careful to distinguish assets that bring income, and other forms of property and equity whose price is purely an illusion supported by speculators' predictions about other speculators' whims.