I've said it before but this way you end up with a (comparatively) boring collection, kind of like listening only to the Top 20.
It's impossible to collect every
type of every coin that has ever existed. I personally have several different 'collections' on the go at any one time, including specialised
type collections.
You could expand on this much further, but the idea about this is to get the fundamentals, the bones of a truly comprehensive world coin
collection. The coins I am talking about would have
had to have made a decisive impact in the
history of
money or coins, or in historical events. The Lydian
Stater for example, introduced the concept of coinage (to the
west at least), whereas an
average, run of the mill copper coin of
medieval Kandy was not as important in the grand scheme of things.
Coins from the more obscure nation states/civilizations could provide the flesh on the bones, but I'm talking about building the skeleton first...