Heathrow is by far the largest airport in the UK, with several times more flights per day than any other, and flights to a broader range of destinations. So it affects a lot more prospective fliers. I looked up European airports and found some mention that Rome and Milan also have this new equipment, but they're both still significantly smaller than Heathrow.

Schiphol had this for a while (several years I think, I don't fly often), but they reversed it a couple of years ago because European regulators didn't agree for some reason, and now liquids are forbidden again (discussed elsewhere in thread). So this surprises me and is news to me.