One of the most prevalent strategic concepts in 5th edition is that of 'MSU', or 'multiple small units'. The MSU strategy is built around redundancy. The idea is that three or four small units, with perhaps a special or heavy weapon or even just hiding in a transport or sitting on objectives, are much harder for the enemy to completely wipe out than a single large unit, and allow fire to be distributed with greater granularity. Not all armies benefit equally from MSU tactics, however, and amongst those who have trouble getting any real worth out of it are the Tau. Oh, Tau cadres often have small units, but that's usually a matter of either a low unit cap (1-3 XV8/88, 1-2 XV8 bodyguards) or a high cost (80 points for one XV88, 62 for one XV8 Fireknife, the 'Devilfish tax' on Pathfinders). There's no real advantage to the Tau in fielding these sorts of small units, and nothing that really ties in to the overall MSU concept. Just because they have small units doesn't mean it's a strategy.
But that might be changing, and it's all thanks to the pulse carbine. Since it only has to wound, not inflict a casualty or an unsaved wound, the pulse carbine's value to the traditional delay-based tactics practised by cadre commanders is much higher than previously believed. Originally, the carbine was thought rather useless; short ranged, assault 1, and you needed about a dozen of them on average to stand a chance of forcing a pinning test on a standard Marine unit. Even worse, if the enemy passed that test, your unit was 18" away, in range for a rapid fire volley next turn or a charge from jump infantry, beasts, cavalry or particularly lucky units with Fleet, which is to say, all those units you least wanted close to your lines and hiding in combat.
But what if, instead of taking twelve Fire Warriors and maybe getting one test off, you could take two units of six, and be as close to certain as possible that you could force two? And of course, it's not just Fire Warriors that carry the pulse carbine; the drones on every Devilfish and Piranha have it, as does every gun drone purchased by XV8s or 88s for ablative wounds. And that means, usually, there are a lot of pulse carbines on the field, in disparate units, each of which can force a pinning test whenever they hit and wound a unit. If you really need to stop something, like deep striking FNP Blood Angels or a squad of Grey Knights assault terminators, one pinning test isn't going to be worth relying on. But what about two, or three, or four? Even Eldar, with their common LD10, might find their luck running out in the face of test after test after test.
Pinning has always been something of a red-headed stepchild of a tactic; between the omnipresent mixture of high saves, high leadership and just-plain-Fearless models, having to hit, wound and force a casualty/unsaved wound just can't be relied on. Especially when only half your shots hit to begin with. But with this new understanding of the pulse carbine's requirements, not only is it more effective on a per-unit basis, its effectiveness actually grows more sharply when you add additional small, mobile, mutually supporting units. Now, obviously this strategy won't work against every army out there; large mobs of Ork boyz and Tyranid creatures in Synapse range, and of course any units with Fearless, won't fail a test no matter how many times you try and force them to. But most of those units won't be dealt with at range by Fire Warriors or Gun Drones anyway, so the switch isn't going to lose you much, and the added mobility may just help a canny cadre commander dance around his enemy until those boyz mobs aren't so big or the surviving Synapse nodes are a little more few and far between. It's a tradeoff, but at least it's not the apparent 'complete sacrifice' it once was.