Hi,
70 g less for 70 $ is not too bad, don't you think?
Of course it depends on your financial situation. Some riders do not care so much about the price and if you want it super light you need to take care for every gram...
I think bhaverchuck pointed it out: for dialed riders and flat only it may be an option. I am not so dialed and I cracked a Mini Mag crank arm. Maybe the titanium crank is even stronger, but I can not imagine that it is as strong as a regular CrMo crank like a Profile Race.
I know that some riders have cracked the KHE titanium crank, for example around the area where the spindle bolt is located. A spline drive sprocket could help here.
So someone needs to test this crank, go ahead!