Our first charger (over 10 years ago) was hard wired because we had no choice. As soon as the installer left I pulled the charger, installed a 14-50 outlet, and moved the charger to a more convenient location.
We now have 3 chargers and all are plug in. If someone wanted to steal one I guess they could, but this has never been a worry. I like the idea that I can easily change out a charger if I need to, nad that I don't have to leave them if I decide to move. I can think of no valid reason that a hard wired unit has advantages over a plug in one. However the advantages of the plug in unit are somewhat minimal.
Toyota RAV4 EV
No longer: Porsche 914 conversion, Mini E, ActiveE, i3 Electronaut Edition