I think it would make sence if beacons are immovable even with movableBlockEntities enabled (or create another command for beacons) since beacons have obsidian in it and are also immovable in Bedrock where block entities such as chests are movable. And with them beeing movable there is no immovable transparent block where it's possible to put redstone dust on it anymore if you want to play with movable chests and other block entities.