There's also the fact that the RNG has a flaw that causes short-term streaks of similar numbers (but at any point in the rage, so the various streaks theoretically balance out).
Any of the automated multi-skill gains (imbuing unravel with a container, cooking a huge stack of fish steaks, etc.) therefore can benefit greatly if they coincide with a streaking result range that qualifies for skill gain. And, given the likelihood of no gain even from a bagful of items, without the streaks being considered, lucking into a streak of 3, 4, 5 or more gains from a bag will be worth attempting.
To use a probability & statistics example, heavily over-simplified,
A short streak of negative results in an experiment with a very small chance of a positive result, would be indistinguishable from normal gaps between positive results, except in scales that would far exceed the population samples are drawn from - and then only if the positive results weren't subject to the same streaks.
On the other hand, streaks of positive results in similar short bursts would be massive outliers on the probability curve if the generator was actually "fair", and having them occur consistantly provides evidence of streaking, as well as holding potential to dramatically shortening the time needed to reach "x" successes.
So, going for 100 skill gains, with a theoretical (without streaks) gain rate of 1 every 50 items, it should take you about 5000 items. At such a low chance of success, even if you DID hit a streak of a really bad result, the streak lasts much shorter than normally, common, random gaps between gains, and there would be no appreciable difference (it might show up if you had to do a million attempts, but you're only doing about 5000). HOWEVER, a streak that is to your benefit is WELL outside the normal distribution range, and therefore have the potential to knock several hundred attempts off the length of your training regimen. The lower the chance of success, the less likely it is for a bad streak to even be apparent(!), and the more positive effect that a good streak will have.
So, do unravel stuff by the bag - but make sure the bags all have quality stuff if doing it to train. You may not actually GET a streak hit in your favor - but even one so throws off the normal distribution curve that the chance is worth it.
