(3) Bitcoin's only intrinsic value is its utility as a method of payment. Its value as an investment depends entirely on that utility.
No, this is not true. A significant portion of bitcoin value comes from its utility as a storage of value: an asset that is scarce, non-confiscatable, exceptionally carriable (cf. gold), pseudonymous, uncorrelated to any traditional asset, and more.
Those properties do not suffice to make an asset into a reliable store of value. (The last one is in fact a defect.)
Consider real estate on Pluto, and suppose that the UN created a body to manage its property register, with an open reliable market, and everybody trusted them to be up and honest for the next 100 years. If, on some day, the market price of 1 square km on Pluto were 1 M$, would you invest that money into it? How would you know that the market price of that land would still be 1 M$ the next day, and not 10$?
By the way, bitcoins CAN be confiscated if the government knows that you have them -- and it will be very hard to invest a significant fortune in bitcoins without the government knowing it.