@jorgestolfi
You have a pretty impressive CV and all that. But to have a fruitful discussion, we can not throw those things around, because eventually we will end up with trowing in the name of Krugman, who has everything that you have and more. We are talking about a man who belives in the broken window fallacy, and who thinks the value of the dollar is supported by guns. The prize he got is given by a central bank, the very bank that invented fiat money.
Your arguments against bitcoin is the standard dozen or so that has been deeply discussed here and largely refuted. With your intelligense you should easily be able to follow the discussion. Is there something in your career that inhibits the free thought? May be you aspire to become a central banker in Brazil, or to the sweedish economy prize? What I do, when discussing bitcoin with someone interested, is to suggest he should get some. Nothing is more inspiring than to have a small value in bitcoin while you consider it. You don't seem to want to have even a small fraction of a bitcoin to own for yourself. Is this for being neutral, so your considerations should carry more weight? Or is it so that you can say in your next application for a job within the establishment, that you never had any bitcoins?
Now, the latest argument against bitcoin is speculators and other bad actors. Is speculation bad? The word has negative connotations, yes, but it is really not well defined. The difference from investors is at best that a speculator takes high risk, but an investor takes small risk. The important point is of course the expected return, and if risky you have to spread the investments a bit.
Assuming you consume one bread a day, why did you not buy two today? Because you speculate that you can buy one tomorrow for the same price. You can speculate about a price going up down or stay the same. It is about using your brain to foresee what is going to happen and act accordingly. That is what we do when we buy and hold. You can not safely call it investing, since it is not capital goods you buy, but another kind of money. The reason for other people to buy bitcoin is irrelevant. The question is, will they, and when they do, how much do they want to hold?
Your second latest argument is that there are possibly infinite other coins that can be made, so the supply is not really limited. For this argument we have in fact data, bitcoin has value, countless altcoins are created each day, but up till now they have not been able to water out bitcoin. There is a reason for it also, the reason is that the traders want to have one type of money if possible, maybe a few more if they have other good qualities that bitcoin has not. The current situation with hundreds of different fiat money types is not in the interest of the traders, it is in the interest of the governments and their cronies. Since the governments are not involved with bitcoin, there need to be only one. There is a small risk that it will be something new, but currently I don't see any real competitor.