Yes it matters. If it's too volatile, merchants won't feel comfortable accepting it as its too much of a risk. Easy answer here. It could be years before bitcoin stabilizes, if ever.
Bitcoin was not only created for the merchant, if merchant is happy for sure traders and investors are happy with the volatility of bitcoin.
Yeah bitcoin is for every body that wants to use it for real. And of course if value of bitcoin is going to be nothing then no one will get interested to it.
But it seems that many are being attracted to bitcoin as the price is keep on increasing this makes the bitcoin to become attractive.
So the price of bitcoin really matters for all of us who are using it for real.