A rather niche observation I’d make while sitting in the Biz Premier carriage of the Heathrow Express is that as things stand anyone who spends ~£5K for Star Alliance Gold status on an airline like LH will get the free upgrade on HEX, but someone spending £35K a year on BA would not. An unusual way to assert dominance over your one and only hub.
Perhaps I’m just bitter - BA have managed to misplace my bag with all my warm clothes in, so I’m about to walk 15min home in just a T-shirt which I am not looking forward to.