Agreed there is nothing that will even come close to repeatability and speed as a well made drill jig. Not even a CNC gantry drill can absolutely repeat multiple set ups without a secure index point
The company I was with in Kuwait was contracted to fabricate some supplemental steel beams for the Burj Khalifa in Dubai to be installed in one of the upper floors somewhere within the building. We were well known for being able to duplicate replacement beams for other companies who had miss counted their run numbers or additional small quantities of fabricated steel were required due to last minute design additions.
Our beam line was top notch with a multi head beam drill in the line capable of drilling both flanges and the web simultaneously.
On this particular instance the original beams had been fabricated on a beam line much the same as ours but the series of holes were off by 1mm accumulative.
that may not sound so bad on a 20 meter long beam with only 2 or 3 sets of holes but the sets of holes on these beams were on a 500 mm spacing so by the time all of the hole sets were drilled the accumulated distance had become significant. Given the size weight and cost of the beams I decided that even though our drill was nearly new and quite capable of precisely spacing the hole sets under normal circumstances, I opted to fabricate a drill jig which would be attached to the spindle of one of the drill heads with 2 sets of holes spaced the proper distances from the set being drilled. the spindle would drill the first set of holes then the beam was advanced by the advancing clamps then a pair of machined pegs would be placed into the previously drilled holes then the spindle would drill 1 hole of the set thee pegs removed and the spindle allowed to complete the series of holes in that set and the beam advanced once again only 3 times during the entire process did our machine fail to advance exactly to the next series at which time all we had to do was release the holding clamps and fudge the beam about .5mm
For a few moments our company was the hero of the day.