This isn't a uniquely American thing to be fair, in the UK it's not unusual to discuss area in terms of football pitches or for very large areas, Wales.
UK should not hold us back with their shenanigans.
If you're trying to communicate 'this much rainforest disappeared' or 'look how large this landmass-sized Antarctic iceberg is' to a wide audience a well-known area is a reasonable way to do it. In Britain basically everyone knows roughly what the size of Wales is relative to the other countries of the UK, even if they don't know its exact size.
I don't play football, nor soccer nor rugby nor baseball or similar sports, just like you most probably don't climb on rock. I am not pushing my metric of '2 spans of typical rope length for alpine tightrope 2-people setup ' or similar obscure metric, do I.