The only thing you can with Z87 is features that you may not need for a low end platform. Suggesting that everyone gets Z87 with a Haswell Pentium is assinine. With Z87 you get more USB/SATA ports, , maybe a better audio chip, SLI/CF, more expansion , and overclocking.
These are things that I do not care about for my HTPC, and I certainly do not plan to upgrade it to a 4770k. Ever. I overclock my desktop but I will not be overclocking my HTPC anytime soon. H81 as a platform also does not perform differently than any other chipset. Z87 gives you more features and overclocking, which is desirable for overclocking SKUs such as the 4770k. These features aren't needed by buyers of light use daily driving systems.
Total cost? 100$. Honestly you'd have to be stupid to get Z87 with a Haswell Celeron. It makes sense with a 4770k. It doesn't make sense with a Pentium or Celeron. But. By all means. If someone wants to buy an overclocking Z87 motherboard for a chip that doesn't overclock? Sure they can do it. Further, If someone wants a low performance chip such as the Kabini, that's their prerogative. I do believe most would opt for the much higher performing and similarly costing platform with the celeron or pentium.
I also do not see desktop SKU power draw being a valid argument in this case; all of these SKUs are very close to each other. You can run any and all of these chips with a 300W PSU. Therefore, even if the Pentium G3220 uses perhaps 15-20 more watts (not sure, just an example) it doesn't matter. All of these run on a 300W PSU. This is not a situation of something like going from a iGPU to a R9-290X which adds 300W and requires a bigger power supply - power consumption can be a valid argument in that context because the differences in graphics power use are vast. But comparing kabini, BT, haswell, celeron on the desktop: These are all usable CPUs on a 300W PSU therefore it does. not. matter. These are all low power consumption chips, and are not a mobile platform, therefore the power differences between kabini and celeron/pentium means little if anything in a desktop context. In a mobile context it might matter. Not here though.