If anyone is wondering. Bella comes with two render engines:
a) a fast one (Saturn), equivalent to Cycles, but can also show dispersion inside gems and handles more indirect caustics
b) a slow one (Atlas), that does full caustics of all kinds.
Here is the difference between the two in a real life example.
Atlas discovering reflective and refractive caustics behind a glass surface
The same thing with Saturn
Atlas discovering subtle highlights reflected on an SSS (Alabaster) material behind glass
Saturn on the same thing. Most reflections are there but less pronounced.
Full image for Atlas
Full image for Saturn (Same Alabaster material)