What does it mean for something work but only at a superficial level? What is the alternative -- working at some deeper level? Either something works, or it does not. If it just gives the appearance of doing something but does not actually do it, then it does not work. (I'm sure this is a brazenly Te perspective, but then in INTJ fashion, I am not used to half-baked results.)
It's the classic expert-itis, to which both INTJs and INTPs are suspect: that one's own personal way of thinking is deep and insightful, and the others' way is superficial.
Both types have blind spots, which the other sees as superficial. Ni-Te in operation can look superficial, but it isn't. Ti-Ne in operation can look flaky, but it isn't.
More specifically, Ni-Te is habitually paying attention to externalities that INTPs tend to (but not always) ignore. Those boundary conditions can change on the fly, which not only changes the set of potential solutions to a problem, but also determines which questions are the right questions to ask. But Ni-Te, in so doing, is somewhat stuck to those externalities, while Ti-Ne is quite capable of covering large classes of general possibilities. So INTPs will see the INTJ solution as correct, insofar as it goes, but it's incomplete, it doesn't take into account all the other possibilities. But the INTPs usually don't see how a mild change of boundary conditions can totally alter the problem space. Ni is always changing problem spaces, trying to figure out the right question to ask. INTPs (and this is more Si-based) tend to stay in a single (very well defined) problem space.
In short, INTJs tend toward solutions that correlate very well with (the currently know version of) reality, and is habitually trying to stay current with reality (Se, Te). This can result in inconsistent and ad-hoc solutions, especially if one isn't paying close attention. ITNPs tend toward solutions that correlate very well with a more generalized perception of reality (Ne, Si), and as such those solutions tend to be self-consistent with each other. This can result in solutions that are generally applicable, but don't really fit with a particular current state of affairs.
Which solution style is better? It comes down to which model of reality is more apt, and how well the specific individual is paying attention to it, AND how well the individual understands the flaws of one's particular approach and adapt for them.