We have it in Germany for years too (in densely populated areas) and my subjective impression is that next to none was using it for a long time but that it's picking up slowly.
For one thing I think these things take years for broad acceptance and for another the current scanners with their bright and large displays are just what was needed to make it attractive for the young and elderly.
Give a retailer a large display, and they will fill it with ads, with the important info in tiny type. Or even a small display. I've seen user-facing credit card terminals where the small screen is 3/4 ads, 1/4 transaction.
If they'd just put up "Place card against screen here" marker that was 1) where the antenna is, and 2) fully synchronized with when the system is ready for a card read...
For one thing I think these things take years for broad acceptance and for another the current scanners with their bright and large displays are just what was needed to make it attractive for the young and elderly.