Yes, such an amount of laptops for a simple chat was ridiculous.
But as a part of Sherlock´s mind palace it makes sense.
BBC was simply messing with things we saw on screen to confuse us. It was the same thing they did with the famous "moving plant" in HLV:

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I cannot live without brainwork. What else is there to live for? Stand at the window there. Was there ever such a dreary, dismal, unprofitable world? See how the yellow fog swirls down the street and drifts across the dun-coloured houses. What could be more hopelessly prosaic and material? What is the use of having powers, Doctor, when one has no field upon which to exert them?
