Good points.

It occurs to me that for less effort than AC SE you can probably get AC E and LH top-tier, which allows upgrades on both LH and UA.

So for the little bit you give up on AC, you pick up quite a lot on LH. For two years.

Now that I think about it, I think you could probably get AC E, LH top-tier and oneworld Sapphire for less effort than AC SE.