Here's some solid analysis:
I think there are three messages to take away from this study:
1) The use of beta-alanine to improve weight-lifting performance and therefore its use in pre-workout or ongoing supplementation for these purposes is still unsupported by scientific study.
2) Even if we were to draw the incorrect extrapolation to weight lifting, BA doesn't seem to confer any effect for exercise less than 60 seconds. Whether or not rep ranges in the 12 and higher range are equivalent to exercise higher than 60 seconds (which I'll entertain for…amusement purposes) is also debatable since weight lifting is cyclical in nature, with rest between sets and it's difficult to determine how much of a role "lower buffering capacity" has in determining technical or absolute failure, not to mention the fact that these studies mostly looked at single bouts of maximal exercise, not multiple sets.
3) The use of beta-alanine to improve cycling or running performance seems to be marginal at best. The arenas in which the effect size of 0.374 was measured (i.e. the 2.85% improvement) are not likely to be the ones in which a 2-3% improvement in time or distance actually matter. In a 2000m rowing race, we're looking at an improvement of around 7 seconds (which would make a difference at the Olympic, or even the National level). In a 40km cycling time trial, we're looking at a 1 minute improvement (which again, would make a difference only at the most elite of competitions). However, only one of these studies actually looked at elite athletes. Would such an effect size be retained at the elite level? We just don't know.