I just ordered the Squarp Instruments Hermod + and planed to place in this case (which sits in front of my big case for best accessibility):
ModularGrid Rack

which is a Intellijel Palette 62 ( 1.2 A (+12 V) / 1.2 A (-12 V) / 500 mA (+5 V)) .

In the manual of the Hermod + it says:

Connect Hermod+ to your eurorack system power with the supplied ribbon cable.
Most eurorack power supplies have a dedicated +5V rail (in addition to the +12V
and –12V rails).
• If your power supply delivers +5V, we recommend to place the « 5V switch » in the
top position, in order to use the +5V rail for the digital circuitry of Hermod+.
Make sure the +5V rail can supply 820mA minimum for powering Hermod+ (and
add +500mA maximum when attaching a controller on USB host).
• If your power supply does not deliver +5V, you may place the switch in the lower
position.
Make sure the +12V rail can supply 400mA for powering Hermod+ (and add
+220mA maximum when attaching a controller on USB host).
In any case, Hermod+ will not be damaged if you use the top position and your
power supply does not deliver the +5V. It will simply not power up.

These are the power specs according Squarp Instruments when not powering via 5v:
Consumption (not using +5V rail) : -12V 20mA, +12V 400mA (add up to +220mA when attaching a controller on USB host)

So If I dont change the PSU of the Palette case i have no choice but powering via +12 & -12v , right?
I dont get whats actually the benefit from powering over the +5v rail, which I have not yet used at all