Ummmm, This trains two entirely different skills that are likely both worth exploring for different reasons.
Soroban is the mental visual manipulation of the abacus. An abacus is a machine. You move the beads and in the end you interpret the result. It removes mental calculation from the process and allows for insanely fast translation of numbers to beads on a string.
I strongly suspect that training your mental visualization skills at speed is a pretty good starting point to developing better general visualization speed and accuracy… Assuming the skills were developed more generally over time…
Mental calculation does not rely on our visual memory very much at all except that it is easier to look at what you are calculating than to look away or calculate without the image of the initial numbers.
Mental calculation seems to develop numeracy and the ability to hold and manipulate symbolic concepts faster and or with more complexity. Again this is likely a skill that is only generalizable through generalized practice; logic, rhetoric, art.
Memory/study skills which are the more common topic of this forum fill another space in the foundation…
There are more; from mindfulness to gymnastics to nutrition and social interaction that could be productively developed and then integrated if one was interested in being something more than a simple worker drone. The challenges of life often interfere and motivation is a limited resource.