I guess you could compare gem boxes and normal obstacles to a question I have heard before: Would you rather have a store that sells things cheap, and have lots of customers, or a store that sells expensive, and gets customers once in a while. It may equal out, or one may profit more than the other.
And to calling something free fair or not, it really depends on how you think. For me, I think that if SC is going to give us gem boxes, they should do it right. And right now, it is not clear if the gem boxes' spawn rate will be rare or consistent, so I am just throwing the question out there to see what others think.

