Spoiler alert: my answer would be "no." But the question is not as ridiculous or irrelevant as it may at first appear. In chapter 25 of Capital, Marx describes relative surplus population as "the pivot upon which the law of demand and supply of labour works." What does that imply? In part, it implies that without the benefits that unemployment confers on capital, there would be less total demand for labour, less employment of labour power and thus less creation of value and surplus value. Of course, that is a counter-factual scenario. Capitalism unable to procure an increasing mass of surplus value would cease to function.
In English and in Italian, at least, publication of a translation of a portion of the Grundrisse nicknamed 'the fragment on machines' preceded publication of the full translation. This has had the consequence of elevating that fragment to iconic status. Moishe Postone, Antonio Negri and others have used the fragment as a 'key' for interpreting and/or criticizing Capital.
Textual evidence suggests, however, that there are actually three closely related fragments on machines in the Grundrisse. The two overlooked fragments illuminate the meaning of some of the most evocative passages in their more celebrated companion. The traditional fragment on machines is on pages 690-712 in the Penguin edition. The other two fragments are on pages 397-401 and 608-610, respectively. All three fragments explore the dialectic of the superfluous [überflüssig] and the necessary [notwendige]. That particular dynamic is not discussed elsewhere in the Grundrisse or in Capital, although it is alluded to in the chapter on accumulation (volume one) and the chapter on the internal contradictions of the law of the tendency of the rate of profit to fall (volume three).
Taken as a whole, the three fragments present the rationale for Marx's assertion, in Capital, that relative surplus population is the pivot (or 'background') of the operation of the laws of supply and demand for labour power.
There is an analogy here between unemployment and machines in that less total value would be produced without either one of them. One might say, then, that unemployment adds value because without it there would be less value created. But that would be one of those semantic paradoxes -- Zeno, et al. -- that turn on the ambiguity of the meaning of "add."