Neural repetition suppression seems to be describing behavioral habituation on a neuronal level. What's the difference between these two terms?
The two concepts are analogous and mutually illustrative, but empirically refer to different levels of analysis: behavioral and neural.
Habituation is a form of non-associative learning, specifically, learning that a stimulus is behaviorally unimportant. If I loudly and repeatedly bang on a metal pot immediately behind your head, you will probably be shocked, then uncomfortable, then annoyed, until you eventually learn to mostly ignore the unimportant sound. It is an effect detected in behavioral measures, rather than neural measures, and which, as any Google search will confirm, is well-established across many species. An example of the term's general usage from Wikipedia (which I hope is sufficient for illustration), noting the emphasis on the behavioral rather than neural scale:
The habituation process is a form of adaptive behavior (or neuroplasticity) that is classified as nonassociative learning. Nonassociative learning is a change in a response to a stimulus that does not involve associating the presented stimulus with another stimulus or event such as reward or punishment.
Repetition suppression is a neural mechanism which attenuates (i.e., gradually decreases the intensity of) signals in the brain when a stimulus is detected repeatedly. Presenting the same visual stimulus repeatedly will therefore cause decreased response in some of the involved groups of visual neurons, which is also a useful effect in a number of behavioral research fields like memory and attention research. Two illustrative examples of the term's usage follow:
Furthermore, single-cell recordings show experience-based changes in perirhinal neuronal firing patterns broadly consistent with item recognition, wherein firing rates decrease in response to previously encountered relative to novel stimuli (Xiang and Brown, 1998). Such firing rate decreases, termed “repetition suppression” ...
Gonsalves, B. D., Kahn, I., Curran, T., Norman, K. A., & Wagner, A. D. (2005). Memory strength and repetition suppression: multimodal imaging of medial temporal cortical contributions to recognition. Neuron, 47(5), 751-761.
Repetition suppression, as manifested by the difference in response amplitude between the first and third repetitions of a target, was stronger for fearful than neutral faces.
Ishai, A., Pessoa, L., Bikle, P. C., & Ungerleider, L. G. (2004). Repetition suppression of faces is modulated by emotion. Proceedings of the National Academy of Sciences of the United States of America, 101(26), 9827-9832.
Clearly, habituation and repetition suppression share a lot of conceptual similarities, but it's important to remember that they are ultimately models of entirely different, if closely related physical phenomena which occur at completely different scales. Behavioral habituation relies to some extent on neural repetition suppression, but it does so through memory, attention and other cognitive systems. Repetition suppression alone is therefore not sufficient to explain behavioral habituation, or vice versa.