When the plan is to put a mostly-controlled short circuit into a residential building you presumably want it located where it won’t be subject to damage from footfalls and furniture and stuff.
You certainly can do resistive heating that’s safe as a flooring material; but you’d be talking comparatively massive construction vs. some sort of thin-film sticker thing that isn’t expected to take having a table dragged across it gracefully.
(edit; that said if you take a particularly flexible view of the objective of dealing with poorly insulated housing stock you could treat this property of resistive heaters as a virtue; and almost definitely shouldn’t.)
