I feel the primary negative effects of this will be felt in the Steam PC Cafe program https://support.steampowered.com/kb_article.php?ref=3303-QWRC-3436
This exists to allow businesses like LAN Cafes and VR centers to gain legal access to games and apps in the Steam Store, at rates that the publisher (NOT STEAM!) sets. For instance, a VR game like Arizona Sunshine, or Job Simulator, is a one-time purchase in the store for consumers. For VR centers, it is a monthly fee ($80 per month per station last time I checked). This fee would have to vary based on the location the key is used in, because no VR arcade in Slovenia for instance can afford to pay the same license fees as one in central London. The economics just aren't there to support the program if it is done on an all-EU basis.