Ability to funnel to any *A partner would be huge. Even in the US market where there are many credit cards that can go to certain airlines, there are some real sweet spots that aren't accessible to people in most markets. Think A3, SK, SA (super cheap biz rewards in Southern Africa pre-COVID), and definitely NH which most markets don't have access to via credit card and even in Japan Amex has a cap of miles per year you can transfer to NH via Membership Rewards (and it's silly low)