Assuming that they can receive and send their money quickly and conveniently with ecash, I speculate that they will never care about the difference between centralized and decentralized.
I share your view. Most people are not critical of how the monetary system works. Other simply don't bother while the rest have so much to think about on a daily basis that they couldn't care less whether the money they are using is centralized or decentralized. Hell, they probably don't even know what decentralized in the realm of money means. I am certain that, at least in my country, 99% of the population don't know the bases on which money is created.
[/quote]Would this not hurt bitcoin as a currency? Would this not only encourage bitcoin to be used as a speculative investment? How about
mainstream adoption?[/quote]
Bitcoin is already hurt as a currency not only because it has evolved more into a speculative asset over the years but also because of certain factors such as fees and confirmation time. I guess Bitcoin will eventually become a sort of an exclusive currency to those who seriously care about decentralization, financial freedom, and perhaps privacy.
I'm afraid the mainstream adoption that we will see in the future is not that the majority of the people in the world are using Bitcoin but that Bitcoin becomes a widely recognized alternative.