Plotting a list of callouts doesn't work

Question

I can plot a bunch of callout's without problems:

Plot[{Callout[Sin[x], "S"], Callout[Cos[x], "C"]}, {x, 0, 2 Pi}]

But, if I create a variable with the list of those callouts and try to plot it, I only get a white plot:

p = {Callout[Sin[x], "S"], Callout[Cos[x], "C"]};
Plot[p, {x, 0, 2 Pi}]

What am I doing wrong?

Any help would be much appreciated (or, in any case, thank you for reading this).