The Art of War wasn’t necessary to break the Tech II, but leaving a runed Nimble Fencer on the field would allow an easy kill on Onimaru if a Star-Crossed Starlet were in hand, without Art of War to grant swift strike.
In this case, I probably should have skipped a worker or two, but once a Garrison lands, there’s so much disadvantage to having skipped, that it’s really tempting to avoid doing so as much as possible. The additional card draw is partially offset by a lower chance of successfully pulling a Garrison on a draw, and once the engine gets rolling, having less gold to power it and more $1+ cards (and especially non-unit cards) to cycle through make it harder to deploy key cards reliably.