You aren't even aware of the techniques -- how can you be skeptical of them?
I'm skeptical of techniques that use the general strategy of using various kinds of cues to perform a kind of deliberate, online reconstruction of the relevant information. I'm not skeptical that they aid memory of information per se, just that they help learning of material in a deep conceptual sense. I don't think encoding information in such a way that it requires conscious effort to reconstruct it from conceptually unrelated cues like mnemonics, imagery and the like (that's what I mean by "unpacking") is much different from just having it available in a book, insofar as it assists in learning in a substantial way. If there are other memory techniques that don't follow that general profile, then my concerns may not apply.
This isn't about learning -- for the last time, it's not about concepts, or linking things together, or learning anything deeply.
Oh. I thought we were talking about the ways in which memory could help you get better grades. If we are, then learning things on a deep conceptual level is very relevant.
I'd have to go find some actual scientific studies to back up my claim, but in my experience the popular memorization techniques are far, far better than simply quizzing yourself repeatedly.
Better for rote memorization, I don't dispute that. Better for learning things on a deep conceptual level? Perhaps not. The role of memory in academic performance far outpaces mere rote memorization, of course.