Seems to me once you start adding stuff like that, you'd very quickly cross the threshhold for "might as well just scratchbuild". The only labor you're saving by starting with a pre-cut (I'm assuming they're pre-cut?) card building is a few minutes with a pencil and a razor blade. Wouldn't take much to spend x3 or more time on detailing than doing the box modeling yourself would've cost.
For me at least, this makes scratchbuilding more worthwhile, as that minor additional +% of total effort is more than balanced out by having full creative control over the design in general. If the creative aspect wasn't attractive to me, I'd probably resent the time spent detailing as much as the time spent box modelling, and go looking for full color print-out buildings than I don't "need" to detail.
Same would
seem to go for MDF/ply stuff... but in wood(or wood-like product)'s case cutting out the boards at home would actually be enough of a PITA to justify trading away that creative control.
Best of both worlds IMO would be the plastic-based foamboard types (best strength/weight ratio, + easy to cut at home), but those are too expensive.
*EDIT* Looking at the Ebay link, it looks like I got your intent wrong, maybe. You're looking at building a foamcore structure, then using the color print outs to "skin" it as alternative to textural detail and paint? Basically using the foamcore layers to create depth for things like doorways and windowsills and such, yes?
If so, I can see that being viable. You
could scratchbuild that way too, but the job of creating templates and assembling the "texture maps" in a photo editor would be more or less equal to the cutting and assembly, if not greater, so doing it with prefab templates/printouts could actually saave you some good time.
I've always kind of wanted to try something like this with paper vehicle patters. I mean, use the patterns as templates for plastic sheet, and separating & layering details with different thicknesses of card.