Where'd you find that stat? I can't find any stats which break out spend by debit and credit card for Ireland, but what I can find is that (as of 2024), there were 7.95 million active debit cards and 1.58 million active credit cards in Ireland (which has 5.2 million people). Given that, the 40% stat seems implausible.
I checked the stats, and about 40% of purchases in Ireland are made by credit card. In the US, it is around 70%.