Urgent Answer Needed for Boxelder Question

We live In NC where tornadoes came through last week and did evil. I watched a 40 foot limb fall from an old boxelder in our backyard. The wind was not the only culprit as the tree was compromised unbeknownst to us.
Yesterday an arborist/treecutter came to advise us as to if the tree should come down or be pruned to eliminate the internally damaged area. He suggested the latter, which is scheduled for Friday, April 29. In fact he said that the diseased part of the tree had been caused by a pruning wound,which allowed some disease to set in. So he is very conservative about creating more pruning sites.
As much as I respect this point of view, my concern is that the tree has a very large and heavy limb directly over an outbuilding in the yard, which happens to house my studio. He did not recommend taking the limb down or even reducing it. In my brief research of boxelders, I have found that they are shortlived and prone to win damage. This limb is like a sword of Damocles over the place that contains all of the materials and tools of my trade. As one can imagine, arborists around here are very busy, what with all the damage Raleigh has sustained and so I thought I'd put this situation on the forum and see if anyone has experience with this type of tree and a viewpoint as to whether I should take the limb down or not.

I am adding another image of the limb over the studio.

What happened on Friday? Did you get the branch cut off?

Well not exactly. Finding no one with an experience like ours with a boxelder, I gathered information from various other sources like the Royal Botanical Garden. All of it repeated the same phrases about "softest of the Maples", and "susceptible to ice and wind" damage. Some sites were downright pejorative, calling it a short-lived junk tree. I presented my misgivings to the arborist with the tree company. He continued to argue that the tree was viable as far as he could determine at that level of inspection (i.e. without the more conclusive diagnostic tests and cuttings, etc.) So we decided to reduce the weight on the overhanging tree, clean up the damaged "open sore" area, and carefully trim other areas of it although this was for my backyard use of clothesline and not for the health of the tree.
In short, we tidied it up, hopefully giving it a new lease on life and reducing the threat to my studio.

I would have taken it down; they regrow fast. The utility tree trimmers took down 3 of mine under the lines last summer, and all have regrown to about 4-6 feet tall already.

Oh. Well, this was the kind of perspective I was looking for Last Week. I will say we live in a community where people do everything they can to protect the canopy. It's the historical area of our city, and there is definite civic encouragement to err on the side of keeping the trees. But nonetheless, if the tree is a problem, down it goes. It's not exactly too late now, but it shall wait.