question

I know, and that's unfortunate, but still the case remains that Blue Sea battery switches and Bussmann surface-mount breakers of that type (you'll note that the breaker is manufactured by Bussmann and supplied to and resold by Blue Sea) are rated for a maximum voltage of 48vDC and as such may only be used on up to 36vNom systems - while still others of the same brands and nearly identical appearance are rated only to 32 or 36vMax for use on up to 24vNom systems. This is independently verifiable on the respective Blue Sea and Bussmann product specification pages.

It is an unfortunate reality that sometimes someone drawing a schematic such as you show here (which to be clear was drawn by an independent consultant to demonstrate the fundamentals of a system, not drawn by Victron directly) does not always individually verify the specifications and limitations of all the various components shown in such a diagram, which is part of why there's an all-caps note in the bottom right corner "when in doubt always consult your dealer" or something to that effect.

Any dealer/distributor/or installer who is familiar with 50-60vDC arc length, switch contact pitting, and the limitations of magnetic arc suppression in low-voltage surface-mount breakers of that type, would recommend that this diagram be used for general reference only while substituting some of the components very generally shown with suitable replacement components such as CBi 125vDC breakers to the controllers and likely Blue Sea / Carling Technologies C-series breakers in place of the rotary battery switches (or other suitable components).