then US dollar is also an investment.
i'll tell you why. where i live the value of local currency is dropping so there are many who are now buying USD to stay ahead of the inflation that is going on. in fact they are investing in USD. and what they are doing matches the description you posted here, they will sell it in the future to get a huge profit.
but it doesn't make USD an investment. US dollar is still a currency no matter what you do with it.
the same thing is true about bitcoin. bitcoin is a currency by nature even if majority are using it as an investment.
Look like there is some people with common sense still. While some people use btc as an asset investment, some people give the real value to it USING it.