A mistake I often encounter is the assumption that one day, a Chinese or Lydian had a great idea and the coin was born and everybody cheered and started using them.
In reality, there is a gradual move from barter to money that took centuries to complete, from well before to well after those "first coins". The mistake colours our interpretation of archeological finds. Suppose an archeologists finds 7 unfinished spades of a type used in Sogdiana (around 300 BC). The temptation will be to conclude: spade workshop stood here. When no evidence of a workshop is found, the conclusions may well change to: traveller lost bunch of spades. However, the spades may be a treasure, hidden in the desert along the trade routes from India and China to central Asia and beyond. The spades are not seen as coins.
It works the same way after the invention of coins. Suppose a Swedish archeologist finds in his back garden a treasure of some jewelry, most broken, mixed with some 8th century coins. It still happens that the first conclusion is "grave of rich person". When no evidence of a grave emerges, the conclusion changes to something like "rich person hid treasure". Fortunately, there are more and more people recognizing a perfectly normal trading stash, rich in hack silver. The Scandinavian tribes did not strike much money of their own and chopped up silver loot to make money. For all practical purposes, those silver chops functioned as "coins", even if the went by weight, do not have a date or a denomination, a standard design or weight and aren't even legal tender.

I realise how difficult it is to do a (very) short history of coins and not mention those considered "the first coins". However, much could be achieved by a good choice of words.
Peter