Well, there you go - "good enough" for >%90 of users right out of the box. :)
While there was a time when small & lightweight required a premium over the similarly outfitted larger 15.6" & 17" models which surely MIGHT still be the case here with a $700 asking price for an 'basic' system that ought to cost in the $300-500 range.
Sure, as many folks have moved much if not most of their 'home & personal' IT needs to their smart phone of choice, there will always be use patterns where a Laptop fits better and is easier to use then a phone or tablet.
Given this until will be transported mostly in a backpack or dedicated sleeve or case, the plastic construction reduces its weight as a full metal chassis is likely unneeded at this price point and usage class.