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.
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.