I would argue that desensitization should be done to take control of your life as opposed to letting stuttering control you. But yes, fluency can be a byproduct. It's a very nuanced topic that I can go on and on about, but in short, it helps stopcthe negative feedback loop, and it helps tell your mind and body that you're ok. The other thing to remember is that desensitization helps recognize that you most likely have a lot of fear related to stuttering. Again, dealing with the fear helps calm down that fight/flight/freeze response our body puts out during stuttering moments. Also, the more comfortable you are with stuttering moments (via desensitization), the more likely you are to put yourself in new speaking situations. The more you do those new speaking situations, you should be able to gain a level of comfort and hypothetically stutter less.