The bright side, if one could even call it that, was that as long as the Dark Lord was currently possessing the body of Ronald Weasley (stuck like a fly on flypaper, more like) he could not materialise anywhere else. So, it behoved them to keep Ronald Weasley comfortably confined, thoroughly warded, et cetera for at least as long as it took them to rustle up any other Horcruxes that might be waiting around.