It’s because a HW circuit is easier to engage, more reliable, higher fidelity and requires less maintenance.

I don't know if you’ve worked with modern audio software but its truly a tangled stack of complexity, incompatibility, license management, etc etc. It can sound and work great once set up, but its touchy stuff when it comes time to make changes, update the OS, etc. as we all know software is notoriously buggy which is far from ideal in a live scenario.