Actually not above 'hobbiest' usage. Its comparable to sales of other comparable things like Arduinos which have sold north of 2M units at this point if you count all the variations.

That said, like the Arduino, there are a small mix of custom-commercial uses in there, some educational where the units are purchased as part of a curriculum, and of course some 'novelty' purchases where people think "I should get one of these" and then never use it again.

So it has good penetration in the hobbiest market which, depending on who you believe is 3 to 5 million 'seats'.