This means you have a sacrifice effect in the Command Zone that you can be ensured of getting for your sacrifice matters (10th most-played archetype on EDHREC.com) and Aristocrats (6th) that cares about this ability
Ive seen a few people still using his or her instead of them, shuffle your/their library vs shuffle, etc
Use cards such as Thousand-Year Elixir and Patriar's Seal to get more than one activation out of Jan Jansen each turn
Yes, you read that right: No cheap Commander stuff
Walking Ballista can fit into a lot of different strategies, and your ability to mess around with it and mod it like a weapon in a game, makes it a truly outstanding card, and definitely one of the best Artifact Creatures in Commander
"Next thing you know, you're spending so much money on stuff that you have no zero knowledge about