I mean if it was significant enough for you to want to modify it either with a direct code edit or an add-on then you would extend/edit the
XF\Data\Currency
class and extend/modify the
getCurrencyData
method.
PHP:
'USD' => ['code' => 'USD', 'symbol' => '$', 'precision' => 2, 'phrase' => 'currency.usd', 'fa' => 'fa-dollar-sign'],
Would become:
PHP:
'USD' => ['code' => 'USD', 'symbol' => '$', 'precision' => 0, 'phrase' => 'currency.usd', 'fa' => 'fa-dollar-sign'],
Though note that a value of
1234.50
would become
1235
in that case due to rounding.