But once bitcoin becomes stable, will people continue to use it? Honestly, from what I see, 99% of people invest in bitcoin for profit, and very few people care about its technology. So if bitcoin is stable, I doubt they will continue to use it. I believe that you and I, and everyone in the market today are interested in the bitcoin price every day.
Well, I don't monitor bitcoin rates every day. If anything significant will happen I'll see that from forum activity.
But okay, about if bitcoin will be interesting without volatility: definitely yes. Don't forget it is a deflationary asset so you expect that even if it is stable it will let you buy a little bit more in a year and any fiat currency (inflationary assets) will give you less in a year. The aim for inflation for US is 2%, so in 1 year 1 dollar becomes cheaper at least for 2% averagely. If bitcoin will be just stable it will give at least those 2%. So people will still be interested in using bitcoin anyway. And this even if we forget about main thing: when you trust your money to banks they control it, if you use bitcoin then control on your money stays at yours.