Values aren’t simply goods. Values are the combination of use-values and exchange-values in capitalism compared to each other through their exchange-values as magnitudes (this is worth $200, not this sock is as useful as this spinning machine).
In so far as exchange is a process, by which commodities are transferred from hands in which they are non-use-values, to hands in which they become use-values, it is a social circulation of matter. The product of one form of useful labour replaces that of another. When once a commodity has found a resting-place, where it can serve as a use-value, it falls out of the sphere of exchange into that of consumption. But the former sphere alone interests us at present. We have, therefore, now to consider exchange from a formal point of view; to investigate the change of form or metamorphosis of commodities which effectuates the social circulation of matter.
The comprehension of this change of form is, as a rule, very imperfect. The cause of this imperfection is, apart from indistinct notions of value itself, that every change of form in a commodity results from the exchange of two commodities, an ordinary one and the money-commodity. If we keep in view the material fact alone that a commodity has been exchanged for gold, we overlook the very thing that we ought to observe — namely, what has happened to the form of the commodity. We overlook the facts that gold, when a mere commodity, is not money, and that when other commodities express their prices in gold, this gold is but the money-form of those commodities themselves. [Marx & Engels Capital 1 Part I Chapter 3 Section 2A Para 2-3 per https://www.marxists.org/archive/marx/works/1867-c1/ch03.htm#S2a (unreliable as an archive due to copyright issues)]
Values aren’t goods as value is only maintained through its continuous movement and expanded reproduction through different forms. Value only exists in the movement of money buying factories, inputs and workers; workers putting inputs through factories to make things; things being sold for more money; and more money being used to buy more factories…
Now it is evident that the circuit M-C-M would be absurd and without meaning if the intention were to exchange by this means two equal sums of money, £100 for £100. The miser’s plan would be far simpler and surer; he sticks to his £100 instead of exposing it to the dangers of circulation. And yet, whether the merchant who has paid £100 for his cotton sells it for £110, or lets it go for £100, or even £50, his money has, at all events, gone through a characteristic and original movement, quite different in kind from that which it goes through in the hands of the peasant who sells corn, and with the money thus set free buys clothes. We have therefore to examine first the distinguishing characteristics of the forms of the circuits M-C-M and C-M-C, and in doing this the real difference that underlies the mere difference of form will reveal itself. [Marx & Engels Capital 1 Part II Chapter 4 Para 7 per https://www.marxists.org/archive/marx/works/1867-c1/ch04.htm (unreliable as an archive due to copyright issues)]
Value is a movement and social process in Marx.
In simple circulation, C-M-C, the value of commodities attained at the most a form independent of their use-values, i.e., the form of money; but that same value now in the circulation M-C-M, or the circulation of capital, suddenly presents itself as an independent substance, endowed with a motion of its own, passing through a life-process of its own, in which money and commodities are mere forms which it assumes and casts off in turn. Nay, more: instead of simply representing the relations of commodities, it enters now, so to say, into private relations with itself. It differentiates itself as original value from itself as surplus-value; as the father differentiates himself from himself qua the son, yet both are one and of one age: for only by the surplus-value of £10 does the £100 originally advanced become capital, and so soon as this takes place, so soon as the son, and by the son, the father, is begotten, so soon does their difference vanish, and they again become one, £110. [Marx & Engels Capital 1 Part II Chapter 4 Para 23 per https://www.marxists.org/archive/marx/works/1867-c1/ch04.htm (unreliable as an archive due to copyright issues)]