I would advise you to split that thought in two.
One (among many) reasons to collect coins is an interest in the history of money and finance. People with this approach have no use for the modern IOM issues but like the earlier issues that served as money and were generally accepted and they sure like to discuss the
symbolism. Completeness is not as important as having a collection that is representative of what was in circulation.
Another (equally valid) approach is to collect coins because of their design. In this line of thought, coins, tokens, medals and other stuff are of interest when they show a relevant theme only and it doesn't matter whether the pieces were used as money, decoration or something else. Completeness is possible in theory, especially if you have a very large budget.
By keeping the two thoughts separate, you don't "have to" buy stuff you don't enjoy. However, in my opinion it is advisable to know the status of the pieces you want to buy: money or not. This is because commercial sellers like the Pobjoy mint want to confuse you maximally on that point in order to sell more, even though your deception could hurt their sales when you decide to stop the frustration of finding out that what you bought isn't what you thought it was and seek another hobby. Knowledge and clear thinking are good weapons to fight the evil marketeers, keep your motivation intact and remain in control of your own money.
Peter
