From my perspective, mindfulness/meditation exercises focus on:
I find that doing these exercises over and over, and becoming comfortable with letting go of thoughts you don't have time to focus on right now, is very applicable to my normal day-to-day thought patterns, and very helpful.
(yes, of course an ADD person naturally has periods of hyperfocus where they need no help with this whatsoever. However, when not in hyperfocus (eg. much of the time you're needing to do productive work), mindfulness plays a very important role.)
(And, yes, being able to "jump to random thoughts" can be very useful in certain circumstances, eg. when you're needing to be creative. Mindfulness exercises are not done with the goal of totally removing the ADD impulses (which is rather difficult to do anyway), but rather to give you another tool in your toolbox that you can pull out and use when you choose to)