Typically when you think of "investment", you are exchanging resources (typically money) for some sort of increased or improved production capacity. For example, buying a new truck so you can increase delivery capacity, or buying a new machine so you can produce more things faster.
Speculation, which is a very, very, very high percentage of all crypto transactions, is merely buying some asset with the intent of selling it later at a higher price. There's a name for this, the "Greater Fool Theory", which is so called because you hope somebody else will buy at a higher price and you won't be the fool holding it when the price declines.
It should be noted that buying stocks on the open market is more akin to speculation than investment, although historically it has provided fairly reliable returns in the aggregate over the long term. It also has the effect of providing liquidity for original investors, so that they can take their gains and invest again elsewhere, which is a trait crypto doesn't necessarily share.
