I believe what you are practicing is standard. As the SM, it is my job to call the show, while my ASMs manage SR and SL. For the scale/demand of productions that I am doing, there isn't time for me to manage props, crew, etc while calling. For ballet, I call from backstage right, but I do let my assistants make the calls until places, as they enjoy doing it.
There have been several instances during tech or a performance where the show Steward (I work with IATSE crews), on-call doctor, house manager or musician rep will want to speak with me while I am calling the show. I always redirect them to my ASM or PA, as I need to focus on the show. I train my assistants to be representatives of the SM team, and therefore represent me to others.
Another reason that I have SM team members on both SR and SL is that they are there for the performers. If someone has an issue on SL and I am on SR, I won't know and can't help them. My ASM on SL can tend to their needs, inform me of what is going on, and she can resolve the situation. The same goes for my PA on SR. If I am in a busy sequence and a performer is hurt/needs attention, she can radio house staff for the doctor and can tend to the performer while the show continues.
You have to be able to trust your team to handle the stage and the performers. If you do micro manage everything, your assistants won't be able to learn how to do the job correctly and you'll hinder yourself, and potentially, the production. Every SM's style is different, and the needs of each production/theater company can vary. Personally, when I have called from a booth, I do make a point to stay backstage making calls either in person or over the PA (depending on what's available) until the 15 minute call. After that call, I need to focus and get myself ready, and head to the booth. (I will check sign-in sheets at the half hour call, as my assistants are usually busy making sure the stage is set at that time.) I see nothing wrong with your "habit", as long as the show is running smoothly and your performers are safe and happy.