They are very ver focused on that connection being water tight for some reason. Maybe its something they hut in a regulatory review, or just being ultra focused on it bein in super confined spaces with trays of liquid.? It is weird though. Its not super high current or voltage there and they could have had a connector straight into the LED head.
Still, in these circumstances I just assume they had a reason.
Its really hard to tell, given that there's absolutely nothing even remotely "water tight" about either their head or their timer. Or the power adapter's connection to the timer, for that matter.
It feels more like they didn't want to have a connector there at all, but it wasn't practical to have the two pieces permanently wired together.
Of course there's always concern about a cable being accidentally yanked out, especially when fiddling with the enlarger head. Maybe that's it.