The quote, "All models are wrong, but some are useful" comes to mind. The OSI model is useful but far from perfect. But you'd be doing students a disservice if you don't teach them about it at a minimum because the OSI model is part of the networking vernacular.
I think there are good arguments to be made that the OSI model has too many layers to be useful. My favorite description of the IP networking model is that IP is the "narrow waist" of internet protocols. Lower levels can vary and upper levels can vary, but IP remains constant (which is why IPv6 is such a nightmare whereas all the other protocols below and above IP have changed significantly with less effort).
The main utility the OSI model has served me is being able to recite it for job interviews.
More honestly, though, I think the OSI model can be used very constructively in teaching by contrasting it with IP. IP is simpler and also less feature-rich; you can learn a lot about IP by noticing which aspects of the OSI model were "left out" from IP (putting it that way muddles the timeline but probably also isn't that inaccurate) and how it varies from what was designed at one point as a "complete" protocol set. But this is all a part of my larger philosophy of a "historical approach" to teaching networking. It's not too uncommon for instructors to do this by discussing X.25 and/or ALOHA early on and then comparing/contrasting IP, but for whatever reason it is typical to introduce the OSI model alongside IP without the historical context of what the OSI model is and isn't useful for today.
