It will still be popular especially if it will be stable in a higher value. People will still appreciate whether its stable or not. Because the value or amount people will ernes will only be based on their work on the strategy and their capabilities to earn.
Yes it will still be popular as a mode of payment since it is fast,flexible and cheaper way to send any amount. Also when it is stable, it will only be used to buy another currency that will be used for trading. But i dont think that it will have a stable value or a fixed vale as the market or the supply and demands dictates the price.
In my opinion, if bitcoin has stable price than it is not too much popular, and also people use it only for transfer amount and little bit some more work but in this way bitcoin would be loss its own value. You know we use bitcoin because of his price increasing and down value, and if bitcoin has stable price, so definitely i will never use it.