I have recently been reading Catherine Ella Laufer’s Hell’s Destruction: An Exploration of Christ’s Descent to the Dead (Surrey: Ashgate, 2013). Much of the book is an historical overview of the ways in which the descent clause has been understood, from its inclusion in the Apostles’ and Athanasian Creeds through the Medieval and Reformation periods to its re-interpretation in Moltmann and Balthasar.
The last chapter, however, moves beyond historical explanation to theological formulation. While I do not find every point of her subsequent formulation compelling, Laufer begins her task by asking a crucial question: “What consequences would there be if the [descensus] clause were removed [from the Creeds]?”
This is not a hypothetical question, but rather a response to explicit suggestions that “He descended to the dead [or hell]” be removed from both Creeds that contain the clause. And it is a question asked with the right criteria in place; Laufer agrees that any theological affirmation must be grounded in Scripture and must not be in conflict with other creedal affirmations. With those guardrails in place, here is her answer:
What consequences would there be if the [descensus] clause were removed [from the Creeds]? Two most serious ones: an incomplete incarnation and a pseudo-resurrection could result. If there is no affirmed belief that Jesus descended to the dead but only that his body was entombed, then it is quite consistent to hold to the Apollinarian view that Christ’s person comprised divine intellect ‘within’ a human body. Bodily death would presumably free the divine intellect to return whence it orginated. . . . Moreover, without the descensus clause the resurrection is called into doubt. . . . Without it, Christ need not truly die upon the cross, for without the descent, the entombed body can merely be in a coma; without the descent, resurrection easily becomes revivification (181-82, emphasis mine).
In other words, without affirming that Jesus descended to the dead, we are left with the possibilities that a) the Son only assumed a human body and not also a human soul and/or b) Jesus’ didn’t actually die, but was revived from a com-like state after being placed in the tomb. The descent clause, at the very least, affirms that Jesus experienced death as all humans do, with his body ceasing to function and his soul departing to the place of the dead. It also affirms, via affirming Jesus’ human soul departing to the place of the dead, that Jesus was really and truly dead, not just in a coma.
While there is more that can be positively stated about the meaning of the doctrine, the descent clause functions, at the very least, as twin guardrails. It protects us against both Apollinarianism and denying that Jesus actually died at the crucifixion.
 Perhaps the most well known, at least among evangelicals, is Wayne Grudem’s argument for excising the phrase. See his “He Did Not Descend into Hell: A Plea for Following Scripture Instead of the Apostles’ Creed,” JETS 34 (1991): 103–13.
 e.g. Affirming the descensus in such a way that it contradicts the affirmation of, say, double judgment in the Athanasian Creed is not appropriate.