I've often seen people meticulously move the cursor around the battlefield, selecting cells, calculating something on the map, and wasting a lot of time on moments where, to make the right decision, even the spinal cord would be enough. Many don't even use quick keys in battle, and you're talking about some hypothetical time-saving with quick combat.
There should be a culture of gameplay and mutual respect first, and if the latter is absent, people will often deliberately waste time, either in retaliation for the opponent's long turns or simply to get on their nerves.