I have a ton of experience with batteries and battery architecture. And i can assure you without hesitation that while Bosch may have their own plugs that include a key sensor, they still connect the battery with the same red and black wire everyone else in the entire industry uses.
Bosch ebike batteries at a minimum have 3 conductors, Pos, Neg & the CAN bus line. Bosch ebike batteries have their own Firmware & record s/no., min, max temp, charge cycles, voltage, etc. and can supply the motor/display this information via the CAN bus, also can be switched on & off via the bus.
With conventional ebike experience you would think you could measure the battery voltage at the + & - conductors too but no, not with the Bosch ebike battery.
Their default state on those conductors is open circuit.
And with your experience, get your horns around
the following picture of an older Bosch ebike BMS, i think you would have to agree that it's a bit more complex than the average bear.
This complexity allows for the following on a dual battery system:
Charging: bat1 charges to approx 80%, then bat2 to approx 80% then both batteries are simultaneously topped off (CV) to 100%.
Usage whilst powering the motor: bat1 is used for approx 5% of it's SOC/DOD, then bat2 for approx 5% of it's SOC/DOD, and repeat.
This keeps the batteries at a similar SOC/DOD and also allows for chemistry/temperatures to settle/cool.
Also safety as to when the bike is off there is no major power on the cable harnesses.