If bitcoin had a stable price it would be popular. Even if the price is stable or not the popularity of this bitcoin is not too much popular. Because many people dont know what is bitcoin. Many people dont need to use it. Many people dont have care about bitcoin. However it is not too much popular right now in the future i think this is the most popular coin even if the coin is not stable price.
Yup correct, the population around the world is 7 billion and 100 million are used only of bitcoin. Most of people used cash for their payment an for other things that want to buy.
And for the user of bitcoin I think it will also become popular, it is not used for investing, trading and etc. but for other online transaction or online shopping who accept it.
It will still popular because it is global currency and with this you can earn money but I think trading and investing destroy.