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.
I think this will take time. To be able for the price to be stable, it should meet some saturation point. As long as there are huge potential new comer to bitcoin, the price will always stay volatile.
Bitcoin was not only created for the merchant, if merchant is happy for sure traders and investors are happy with the volatility of bitcoin.
Same way it was not created to investors alone.
Does the price matter, i guess to some extent but for me its more about the stability and growth that is more important to me at this time.
In general this is the most important but well I'm just a trader, i should maximize my profit if I can.