Years ago when Jim Smith came to voice my system, he spent a couple of hours the night before listening and assessing the issues. Before he left for the night he asked me to do two things by morning before he started his work. One was to damp the vibration of the piano in the room. The other was to raise the height of the sofa cushions by a few inches. I got two furniture blankets for the piano, and ripped a piece of plywood to insert under the cushions of my listening sofa. He then started the serious work of listening and adjusting.
You are right that everything matters. And Jim, with his trained ears, certainly heard more of the issues that I did.
I do appreciate David's and Steve's point though. If the OP does not hear a difference in his room and system, he should do as he pleases. Actually, to your point, he should do as he pleases, regardless. What each of us chooses to do is a different matter depending on our objectives. It seems the OP wants opinions about his coffee table and perhaps, though not asking, may appreciate other suggestions too. It's a good subject to discuss.