User blog comment:Ducksoup/The Future of Infoboxes on Wikia/@comment-5590118-20150825212321/@comment-24473195-20150825215212

That's because it would end up being the same as the current situation with franken-templates (templates with parserfunctions inside templates with #ismobile), and it wouldn't be able to account for future html5 changes or new features introduced by wikia. The idea is to reduce the parserfunctions not increase them. That's something that the potBoxes accomplish quite well for example.

I can't speak for staff. But the general idea is to separate presentation (the way stuff is seen) from storage (how stuff is stored) and processing (how stuff is formatted). Consider something like the. "We" don't really know how it is implemented, or if it is even compatible with some devices, but we simply  use it with no worry about platform specific syntax. Mediawiki/wikia formats it for the specific devices making the use very simple.

One advantage is that even if wikia abandons this extension at a later stage, it is quite easy to write a bot or script to convert all the infoboxes to use in another platform, even one that doesn't use mediawiki software. Something that in many cases is impossible with franken-templates.