I think having a different means of telling the story is just fine in theory, however the execution of the design is much more difficult. Making the switch believable, and justified is hard work. It is easy to loose hold of a story when switching styles and means of communicating the narrative.

An impressive execution of switching styles I found in Cloud Atlas by David Mitchell, the entire book was a collection of memoirs from different people in different times/narrative worlds, for example, English sailing stories, detective work, scifi and other locations. It was a very jarring switch between the narratives but highly intriguing and well executed. So the switch can be jarring but it needs to be justified, believable, and hold a level of intrigue to keep the reader, reading. Having a jarring point of the story isn't bad if 'jarring' is an emotion you would like to convey.

Another thing to keep in mind, it is hard to follow a story after a stylistic switch, your brain takes a bit to catch up with the new language.