Two thoughts on situations where the 555 may be preferable, if anyone has experience how these compare :

1. Low-noise applications. I’d naively expect the 555 to be less noisy than a clocked digital microcontroller, though it’s been awhile since I’ve worked in this space.

2. Low power applications. How does latent power draw compare between a 555 and a typical low power microcontroller?

> Low power applications. How does latent power draw compare between a 555 and a typical low power microcontroller?

The 555 is very power hungry compared to a typical cheap low-power microcontroller. IIRC there are lower power variants but the 555 still fundamentally does timing by draining current through a resistor, which is going to result in losses.

A micro is far superior on both these metrics.

> I’d naively expect the 555 to be less noisy than a clocked digital microcontroller

TTL ones were exceptionally noisy because the output transistors "shot through" - both output transistors would conduct for a moment shorting the supply rail to ground and crowbarring ridiculous interference onto other parts of the circuit.