I get your point but this is not the case with many people here. Those who are bullish on the future price of bitcoin dont really take into account the expenditure behind their investments. This is risky though and not advisable.

What you said - "unnecessary money" -- this is a oxymoron. Because money is never unnecessary unless you are living in a lap of luxury where you a lot of ancestral inheritance to waste on. So finding out some cash good enough to buy bitcoin with is often frustrating for a common man. Still my point is that we should keep aside some cash to buy coins everytime the market dips upto a limit that is sustainable.