Can Solid State Relays be used "anywhere"?
Yes. In the circuit you have drawn you want to use SSR's instead of mechanical relays as you will be hot switching them (i.e. current or voltage is present when you open or close the connection) and this will decrease the lifetime of mechanical relays. SSR's do not have this effect.

However, mechanical relays have an advantage that when they are open, they are OPEN! You get great isolation when they are open. There is no leakage and low capacitance. SSR's have a tradeoff of on resistance vs capacitance. The product of that R x C is a constant for most SSR's product families. Thus if you want low on resistance, you also get higher off capacitance.

one other advantage of SSR's is they open and close much faster than most mechanical relays. An advantage for mechanical relays is their on resistance is usually much lower than SSR's. So it all depends on what you are trying to optimize for...