Im American but have heard it’s common for 2-by imperial lumber units be used in Canada and uk for example. But metric would be used for cuts (which i think is easier often too)
Given a 2x4 is 1.75 by 3.75 inches, it sure doesn't make using Imperial measure any easier than metric. It's more that certain demographics are oppositional-defiant when it comes to change and they tend to make up the "base" of a powerful political parry.
Many years ago, probably about 40 years or so, I remember my dad pointing out plasterboard in the building supplies store that was marked as 1200mm x 8'6", because standard UK ceilings are 8'6" but everything else (kitchen units and appliances for example) are in multiples of 600mm...