Re: Yes
If I recall from undergraduate economics, other features that will help a currency union work:
- free movement of labour allowing migration from poorer to richer areas. The US scores well here, but Britain less so (for several reasons such as regional disparities in house prices and a lack of social housing down south making it hard to up sticks); free movement is possible in the EU, but language and cultural barriers greatly lessen its incidence compared to America.
- a financial system (whether banks, bond markets, stock markets) able to transfer people's savings to investors across the system as a whole: the $ and £ areas do well on this, but the eurozone lacks continent-wide banks and makes less use of shares and bonds to raise money for businesses than in the US.
- a common legal system so contracts, bankruptcies, etc. dealt with in a predictable way in the event of a "shock": US and UK have this: Eurozone less so.
- free trade in goods - US, UK and EU all have this within the currency areas.
- free trade in services - EU still has barriers in place here: e.g. different legal arrangements, regulatory arrangements for the professions. So does the US to a degree with State-level regulation of some services.
There were probably other factors I forgot. I am pleased to read an article that mentions optimum currency areas: anyone looking at the problem without using this lens will probably make the same mistake the Euro's architects did, i.e. look at the currency as a political project, rather than an economic one.
Biting the hand that feeds IT
