we need to deprecate language file lang/en/currencies.php because it is very unlikely to be translated
Instead the list of world currencies may be stored in DB. Actually additional information such as "minor unit" might be stored as well.

As an additional idea: we may think about populating list of currencies for paypal enrollment also from this list (maybe mark some currencies as "major"?)

Also Apu suggested subscribing to RSS about changing in this list. Or maybe create MDLQA to 'check that the list is up-to-date'