Looking at Ameniti somewhat objectively and as an entire package, it's not that bad a deal. Ordering 25,000 Personal Miles from UA will run you $696.98. And the two RCC passes are worth $50 each (based on UA's $50 RCC Day Pass). So it's a heck of a deal if you need/desire the miles and the passes, even if you never take advantage of the two-for-one deal.
And if you stay at SPG properties, you get automatic Gold which supposedly means something. And if you rent luxury cars from Hertz (as I happen to), you get some goodies there. Plus the other things.
So yes, the two-for-one flight offer means nothing to most of us (I'm one of the rare-bird FTers who flies international on Y fares, and even then it's not full-fare Y [usually half or less of the top end Y fare] so I don't know if my fares would apply).
And, of course, with UA soon to leave Australia in the face of the SQ/QF A380 juggernaut, you'll need to pay a C fare for that Raffles seat so Ameniti might not be a bad idea if you and your significant other want to travel to the Land Down Under.