I had the same rationale. I just needed the torx bits. 4mm actually suits me better.
I assume these are mostly for disassembling and repairing, where you sometimes need a narrower bit if the screw is deeply recessed in a housing. The bit length might allow it to be inserted deeper too.
SKU 3811000's handle looks a bit like a Sandvik handle which are my all time favorite screwdrivers.