I don't work in NLP either, but from my understanding, the boundary between syntax and semantics is never as clean as one might imagine, and each language draws the boundary differently, so in general the utility of just looking at syntax can greatly vary.
Another issue is that many real life sentences have more than one possible parse, and we use context and semantics to disambiguate, e.g. how do you parse 'fruit flies like a banana'.
Another issue is that many real life sentences have more than one possible parse, and we use context and semantics to disambiguate, e.g. how do you parse 'fruit flies like a banana'.