Well, it could be a kind of a pun or play on words (like an English example that you posted in another thread).
I guess that tonal ambiguity caused by tone sandhi might lead to a misinterpretation of the intention in some cases. As a very contrived example, say someone asks you what you are doing, and you say you’re buying water with “買水”. I guess that would be pronounced with a rising tone on the 買. I think that’s basically the same pronunciation as 埋, which could then mean that you’re burying water, which conceivably you might do if you had several bottles or containers of contaminated water that needed to be buried. Yes, contrived, but perhaps this is the sort of thing being referred to.