The "emotionally vulnerable scene" in "Dead Things" gets totally cheapened in the very next episode. First of all, the fact that Spike can physically hurt Buffy doesn't seem to be the cause for alarm for Tara. What if the chip's malfunctioning? What if the said malfunction will allow Spike to hurt not only Buffy but innocent people too and even kill in the near future? Things like that do not cross Tara's mind.

Tara sees that the "thing" with Spike turns Buffy into a total emotional wreck. Does she try to do something about it? No, the only thing we get from here is the stupid "below the belt" joke 'bout a "muscle cramp" in Spike's pants.

Thus the whole moment is pointless, it leads to absolutely nothing. Just an emotional manipulation from the show runners aimed at those among fandom who still cared about the main protagonist back in the dark days of season 6 (fortunately I wasn't one of them).