I used to think that having judges obligated for a couple of rounds per student rather than for the whole tournament was problematic at its core. Actually, I still do. When I do the math, looking at the worst-case scenarios shows me that overall teams will get lesser prefs with per-round than per-tournament commitments. I have come to believe, however, that I am either a voice crying in the wilderness or that I'm wrong. In any case, no one cares. What people do care about is knowing who's in for how many rounds—too many tournament directors make side deals with certain teams, invisible to everyone else doing their prefs—and getting the fewest rounds for themselves so that they can scout and cut evidence and do all this other stilly stuff that is popular in the $ircuit. So I've changed my tune. If you want to see how, you can read about it here: http://www.jimmenick.com/vault/obligations.pdf
As a practical matter in the tab room, I don't know how much difference it makes, at least at the high school level. I get the impression that at college tournaments all the judges are only in for a couple of rounds, making tabbing a little more interesting and fun, whereas at high school tournaments, if Bigle X is any indication, most judges are in for at least 4, and the majority are in for the full 6. Not even the issue I would like to make of it, in other words.
My plan going forward is that next year we'll introduce it into all the college tournaments for LD, then at some point go with it for PF too. The point is, if you're going to have strikes in PF, and you're going to have a lot of schools with one-day judges (which is pretty normal for local-ish teams), you should let the strikers know who's a half and who isn't. Once you get the LD schools used to it, most of the PF schools will already know what to do because they do both. The rest will learn quickly enough, as they have with e-balloting.
It must be 2018.