It's not specific to cameras that low humidity causes problems: -
Too low humidity may make materials brittle
Also this: -
a very low humidity level favors the build-up of static electricity, which may result in spontaneous shutdown of computers when discharges occur
This is stated on this wiki page and I read "computers" as any non-trivial electronic circuit.
The full paragraph is: -
Many electronic devices have humidity specifications, for example, 5%
to 45%. At the top end of the range, moisture may increase the
conductivity of permeable insulators leading to malfunction. Too low
humidity may make materials brittle. A particular danger to electronic
items, regardless of the stated operating humidity range, is
condensation. When an electronic item is moved from a cold place (e.g.
garage, car, shed, an air conditioned space in the tropics) to a warm
humid place (house, outside tropics), condensation may coat circuit
boards and other insulators, leading to short circuit inside the
equipment. Such short circuits may cause substantial permanent damage
if the equipment is powered on before the condensation has evaporated.
A similar condensation effect can often be observed when a person
wearing glasses comes in from the cold (i.e. the glasses become
foggy). It is advisable to allow electronic equipment to
acclimatise for several hours, after being brought in from the cold,
before powering on. Some electronic devices can detect such a change
and indicate, when plugged in and usually with a small droplet symbol,
that they cannot be used until the risk from condensation has passed.
In situations where time is critical, increasing air flow through the
device's internals, such as removing the side panel from a PC case and
directing a fan to blow into the case, will reduce significantly the
time needed to acclimatise to the new environment.
In contrast, a very low humidity level favors the build-up of static
electricity, which may result in spontaneous shutdown of computers
when discharges occur. Apart from spurious erratic function,
electrostatic discharges can cause dielectric breakdown in solid state
devices, resulting in irreversible damage. Data centers often monitor
relative humidity levels for these reasons.