That might matter for a cluster, but that's (obviously) not the target market for a Pi.
If you only have less than $100 to spend, a better $/FLOPS ratio of a MacBook (or anything else, really) doesn't matter. One is available, one is plainly not.
For people that CAN spend enough this usually is just a (third? nth?) gadget to play with. Like in the article (because, it's really just a neat way of playing with gadgets and lego, not 'useful' in any sense that can be quantified).
If you only have less than $100 to spend, a better $/FLOPS ratio of a MacBook (or anything else, really) doesn't matter. One is available, one is plainly not.
For people that CAN spend enough this usually is just a (third? nth?) gadget to play with. Like in the article (because, it's really just a neat way of playing with gadgets and lego, not 'useful' in any sense that can be quantified).