I’m surprised they’re making such a big deal. My FSA K-Force cranks are 620g including rings and BB.
As for the folding of the rings, I’m going to go out on a limb and say that is bullshit (excluding crash damage and manufacturing defects).
First bit I agree with.
Last bit I’m not so sure, I’ve an SL-K compact (rarely use the 36, but the 50 to 13-27 seems the perfet range for me), the chainrings are as flexy as a paper plate, they rub the mech under load, and have developed a permenant bend ov about 3mm. And I’m no Caverndish!
On the other hand those rings are pretty light (IIRC the cranks are ~DA weight, the extra lightness is in the rings), so ‘normal’ shimano rings would be fine.
And cost wise the HT2 rings are silly, but I don’t think I’ve ever worn out an outer ring on the road bike (commuter excluded) so it’s a non issue?