Session bus vs system bus for an embedded system

[Alan Martinovic]

Hi,
I'm exploring D-bus as the IPC backbone for an
architecture of a Linux based embedded system
(IoT gateway).

It's a GUI-less, headless system that developers
access via UART or SSH, and physical users never
access directly.

I couldn't get some of the default tools to run:

# dbus-monitor
    Failed to open connection to session bus: Unable to autolaunch a
dbus-daemon without a $DISPLAY for X11

which expanded to the library I was exploring that
had examples depending on the session bus:
https://github.com/ldo/dbussy_examples/issues/1

Given the issues and the nature of the system,
I kind of assumed it makes sense to
ignore the session bus and just base everything
on the system bus. That was the starting assumption
just to get some temporarily stable ground to
build on, don't yet have any strong arguments for or against.

Would like to hear you opinions on this design approach.
Is there value in getting the session bus working
an use it instead of a system bus for a single user
embedded system?