If he does it sometimes that doesn't have to mean he's good at it. (bar primavera and Italy matches). In that video it's mostly about his passes, while content of the video has been the previous 5 years. He's more of a box-to-box player, considering he's everywhere...and nowhere at the same time. I still don't think he's good at beating his opponent. Maybe he is, but he does that in every 10th match.
Good finisher? That's IMO just exaggeration because he played like 100 matches in Serie A and he scored like 10 goals. 4 goals while he was at Empoli in 2007/08 and now in this season. He does not finds himself in a position infront of the goal that often I think. It's like saying Aquilani is a good finisher, while he's not that great really. This is not a bash, because it's not Marchisio's job to nail goals, I just don't see the point of classifying him as a good finisher.
However, I think his technique is very good. He does not lose ball... I've rarely seen him do that at least. IMO that would be his strongest ability he's showing. That and calmness. His passes are good, but then again he prefers the short ones.