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.
In my personal point of view, the price of bitcoin really matters because many investors are looking on the price pattern before investing their money. If the price of bitcoin will be stable and promising, more people will be encouraged to use and invest on it. On the other hand, if its price will be unstable and falls regularly, encouraging investors will be hard and nobody will be interested to use bitcoin because they will think it is just a scam. If that happen, the future of bitcoin will be doomed. That's the reason why signature campaigns play an important role so bitcoin will be trending. Then, more people will be educated regarding how does bitcoin works then it will make a way to stabilized the bitcoin price so, more investors will be encouraged to invest on it. I have a great trust that as the time goes by, the price of bitcoin will be stable with promising price.