When Jim Roger's talks about currency collapse. He is of course talking about a USD collapse. Bitcoin needs to be readily convertible into strong currencies. Without this feature, Bitcoin would be worthless.
You've got it completely backwards.
Bitcoin is a currency, not money. That's why low scalability is completely counterintuitive to it's value proposition. The only way it can derive value is by tons of people using it in every day transactions, NOT a tiny number of people attempting to use it as a settlement layer or generational store of wealth because gold and silver are far superior for that purpose.
Sounds all a bit Mike Maloney to me. Bitcoin is neither currency nor money. It is not issued by any government decree. No authority seeks to collect taxes from it's citizens in Bitcoin, and it has no inherent value. i.e. if a government were to ban Bitcoin being used to transfer wealth, nobody would want it just for it's own sake, such as gold or silver.
Bitcoin is a commodity. It's utility is fast transfer of wealth with the volume of wealth exchangeable per unit, being measured in a wide array of global currencies (but totally tracking the USD price) being totally dependent on the antics taking place on a few unregulated and totally corrupt exchanges. And of course, Bitcoin's value is not derived from millions of people using it in everyday transactions. Indeed, in the UK the few early 'adopters' of Bitcoin payment systems seem to have abandoned it already, as Western consumers just don't have one single advantage in using Bitcoin for legitimate purchases, quite the opposite infact, even if someone actually holds Bitcoin, he is better paying for his new 50" TV with debit/credit card. Bitcoin's value is derived 95% from pure speculation. Not least of all being pushed up by venture capitalists who have invested up to their eyeballs in Bitcoin in one way or the other, and who are desperate to see it work. (in the long-run, it won't)