Designing a low-budget gadget.
Needs a couple of rudimentary chips. Little gates, style of thing.
Just sprouted a requirement for a rather basic timer.
A low-end AVR microcontroller costs about the same as a 555.
And doesn't need external timing components.
And can perform the functions of those gates, too, thank you very much.
All of which makes for a gadget that's not comprehensible from the schematic, but what the heck.
Oh, and it'll probably take an hour to develop the firmware, and a few seconds per unit to program the MCU. But, with the lower parts cost and the lower part count, I rather suspect it really does come out cheaper overall.
No, I'm not just-for-giggles going to design in a low-end Cortex M0 part, just to have a Powerful 32-Bit 555-Replacement Chip. A low-end AVR is still cheaper than a low-end ARM, comes in a more convenient package, and I'm already up to speed on the development tools.