First off, I like to state that Michael Saylor sounded like a self-centred person there. Why wouldn't someone have a plan to pass their Bitcoin to a heir, friend or loved one if they knew they were going to die at a particular time like he stated? That's pure selfishness.
There are many reasons why MS or anyone
1. if you dont have an heir
2. if you have a distant relation but does not show any interest in your life
3. if you choose not to
...because in the end of the day its MS' or you choice!
Me - I'll be leaving it to my kid, if things change for whatever reason it will be burned.