Yes, there'd be an extra wire to the power supply module, but that seems fine for a modular.
Maybe other's modular synths look/work differently than mine, but when all the panels are installed, there is no way to pull a cable from underneath the panels/inside the case to the outside, without drilling new holes through some panel or the sides of the case. So not sure how you'd pull a cable from the power supply to the front side of a panel when it's closed like that. My case is a Intellijel Palette 104HP, maybe other cases expose the power supply to the outside?