Comment by jan_Sate

The form factor. It's tiny compared with mini PC. Unlike other SBC, the software support's good that it just work as advertised (GPIO, graphic hardware acceleration, etc.). If you're using it for work, it also has stable supply chain / commitment that you can ensure to be able to obtain a unit in at least the next few years.

But you're right. It's pretty overpriced for its performance. If I'm after the GPIO I'd just use a microcontroller. If I'm setting up a headless server I'd just use pretty much any other SBCs or mini PC. I'm personally not a big fan of Raspberry Pi.

The cheap Raspberry Pi's still available as Raspberry Pi Zero tho, if that's what you're after.