I've done quite a bit of club building over the last 30 years. What I can say, is that alignment of one form or another in iron
sets
can be beneficial in achieving a consistent flex slope throughout the set. This means the flex is matched progressively through the set to give the best possible frequency for each club as it descends in length through the set.
Dynamic Gold, quite possibly the most popular shaft of all time, benefits from this form of alignment during building. It really makes a discernible difference in feel through the set if they aren't aligned properly and the frequency slope is all over the place - it can make one club feel like a stiff and another feel like x-flex in extreme cases.
Puring, or rather SST Puring, is their take on alignment and a proprietary process which identifies the "optimal" orientation of the shaft using a machine and software. However (and it is a big HOWEVER) it doesn't necessarily match the frequency slope in the SET if it isn't cross checked for frequency with the heads you intend to use. Moreover, if you've only had one club pured (and not the whole set) it's not really going to match anything and is basically a waste of money.
A better bet would be to have your set built by a club maker who can align your set using FLO (flat line oscillation) and frequency checking techniques. A lot has to do with the actual shaft you are using and what you need to do with it, but at least it gives a finished result. Puring one club in a set of irons is pretty meaningless.