This.For me, it's like a hobby. It's entertaining and thought-provoking. I type friends/family/celebs for fun, but it's not like it changes my impression of them. They are still the same people they always were. It's really funny to see my interaction with them in retrospect after figuring out their type too. I also find it interesting to make the connection between two people who give me the same "vibe" but are also very different (oooh, they are both ESFPs!).
I also think it is useful in the sense that it can help you to see that not everyone has the same thought process as you. I mean, I knew that to begin with, but grasping cognitive functions really explains the differences. I view the types as caricatures and generalizations of how the functions often work together, not as fully accurate descriptions of individuals.
It's comforting for me to know my own type and know that I am not an alien, and to help me see my strengths (which is something I often don't see) and my weaknesses in a more objective way.
I think people who are offended by MBTI and by people making generalizations based on it actually take MBTI more seriously. I think the generalizations mostly open up productive discussion and broaden people's views on types. When you understand the thought process behind certain behavior, it can make it less annoying or offensive. You get a glimpse of where other people are coming from.