It maybe makes more sense to you, but an opto with a suitable resistor (and zener if you want some extra protection) is far simpler. You can also add a capacitor across the opto if you want a simple hardware debounce.

But anyway, why D2? If it's a solid state relay, then you don't get any surges, so it's not doing anything.
Shouldn't R6 be connected directly to ground for quicker switching?
Fair enough a large capacitor over the input, but 100uF for C2 seems a bit excessive.
In fact, shouldn't R6 be tied to gnd to provide the voltage divider along with R1 and R2 for Q1?


It all seems a bit over complicated to me.