Altium has only recenty started adding the features it needs to compete with Allegro and Xpedition. It's historically been oriented towards small-team efforts in the same niche as OrCAD and PADS.
The argument I see for Flux is the "FAE in a box" sorts of features for educating hobbyists and early-career design engineers while keeping them out of trouble. The person I imagine would otherwise not done a PCB at all. Someone who instead would have wired up up a bunch of prefab Arduino-type dev boards or bought small power supplies, DIN mount relays, and so on. Those features put a lot of things within the reach of technicians, panel designers, and systems integrators.
The argument I see for Flux is the "FAE in a box" sorts of features for educating hobbyists and early-career design engineers while keeping them out of trouble. The person I imagine would otherwise not done a PCB at all. Someone who instead would have wired up up a bunch of prefab Arduino-type dev boards or bought small power supplies, DIN mount relays, and so on. Those features put a lot of things within the reach of technicians, panel designers, and systems integrators.