My way of describing this concept to clients (especially adults with ADHD as they struggle to make their ability to hyperfocus a positive rather than a negative) is, "When what you want to do and what you have to do are the same thing, you're in a magical 'sweet spot' that you can leverage to work in your favor." But it does require a balancing act, as it can lead to excess if you don't use this sweet spot wisely. Kind of meaning you don't want to "overspend" this advantage or it ceases to be a positive in your life.
Adding the third leg of self care is a great way to illustrate exactly why this is important. Great graphic too!