In many theatres, the stage manager calling the show is running things from backstage. There is often a stage manager’s station in the wings with a podium, a light, a headset, and maybe a few controls for house lights and cue lights. It’s understandable that some would want to call a show from offstage; they have easy access to the stage if something goes wrong. The problem, however, is that it’s really hard to tell what’s going on from back there.
The booth is a much better place to be when calling a show. You can see the entire stage most of the time, and you see what the audience sees. If something gets left onstage that shouldn’t be, your view of it isn’t blocked by drapery and cast members crowding the wings waiting to enter. If there’s a problem with a lighting cue, you have a much better chance of noticing. Sound backstage is very different than what the audience is hearing, but if you’re in the booth, you will be able to tell if a sound level is way off.
It’s true that you won’t be able to run onstage and fix whatever it is you see that’s wrong, so it is important to have one or more trustworthy assistant stage managers or techies on the headsets backstage. Tell them to fix whatever the problem is, then you can get back to concentrating on calling the show. In a cue-heavy show, it’s very easy to get distracted and miss cues if you’re also doing tasks yourself backstage.
You may be calling a show from backstage because “that’s how they do it on broadway”. The truth is, that became a thing because many old theatres on broadway didn’t have booths. If you are lucky enough to have one, you should use it! If you don’t, then do the best you can from backstage. Setting up a monitor hooked to an infrared camera will help you see what’s going on from the house’s point of view, but there’s no substitute for being able to see it with your own eyes.