It's pretty bothersome to me because it can keep me awake but other than that I used to find it entertaining. I lost the use of my hands for some time and I began to play music in my head more and more to make up for it, but purposefully playing music in the head turned out to be a really bad idea lol.
As far as mindfulness, I think the end goal of mindfulness is to maintain a mindfulness mindset everywhere you go. So in other words, your efforts to stay in the present moment shouldn't stop after a concentrated mindfulness session ends. I think the real benefits are supposed to be from applying what you learn in those concentrated sessions throughout the day.
On that note I'll say that mindfulness has taken a long time for me to learn, more than a year later and I still have so much room to grow.