Not a dumb question at all.
My educated guess - they are there for decorum more than actual protection.
I mean seriously - what’s a single LE officer gonna do if someone want to walk wearing a suicide vest - nothing. Drug dealing ? They will just take it to edge of the property - never inside in view of cameras.
Those assignments typically pay pretty well and are cushy jobs. K9 handlers tend to be senior officers - so it’s just some veteran getting paid to act like a mannequin at the front door. The “real” security lurks upstairs and discreetly deals with trouble.