Making less than 0.1 of a difference is a huge assumption on your part. That might be the case for some people, if they don't use MLS often, they get it about right and so maybe only one score in their top 8 is a shot different than it would have been had they holed out.
However, what about people who use MLS frequently? Guys who may play in quite a few fourball comps, and may not need to hole out for maybe 6-9 holes a round. Or even 2-3 holes a round. They could have a lot of MLS holes on most of their scores. The guidelines say (reading on Google) they should add 2-3 shots every time they are 5 feet to 20 yards away. If they generally play until they are 5feet to 15 feet from hole before picking up, and then add 2 shots (or God forbid 3 shots) to score, that would just be ridiculous. A distance that is basically not 3 putt territory, and could well be a distance many 1 putts could be achieved. Their scores could be several shots worse than it would have been if they holed out.
On flip side, players who pick up before they even get to green may he able to put a score down that flatters them. They may be horrible pitchers and chippers, but just add 3-4 shots.