What actually matter is not the actual price, it's the trend.
If the price is stable or rising, the adoption increases. People and businesses get more confident in bitcoin and start using it. More miners start up their gears.
If the price is falling, people get scared / suspicious and will go away from bitcoin.
I agree that the trend of bitcoin matters but the thing is there is a trend because of what? The answer is obviously by it price or value development. Because the changes on bitcoin price or increased on it makes people more dependent or more attached to bitcoin so its development depends on the support of the user on how they will used bitcoin on transaction or investment. So the changes or developments happened on bitcoin can bring great thing about bitcoin so for me it matters just like the trend matters to bitcoin.