Why can't porcelain capacitors be used for communication?

Some friends have suggested that the withstand voltage indicated by the ceramic capacitor refers to the DC voltage. Is the capacitor useful for DC? Is the ceramic dielectric capacitor not a component that works in an AC circuit?

The ceramic dielectric capacitor is formed by extruding a high dielectric constant capacitor ceramic (barium titanate titanate) into a circular tube, a disk or a disk as a medium, and plating the silver on the ceramic as an electrode by a fire infiltration method. It is divided into high frequency porcelain and low frequency porcelain. A capacitor with a small positive temperature coefficient of capacitance for use in a highly stable tank circuit as a loop capacitor and a pad capacitor.

1) The capacitor withstand voltage parameter generally refers to the large voltage that can be allowed under the limited leakage current parameter. In actual test, it is easier to measure with DC voltage. Because the capacitor itself can pass the alternating current, it will drown the leakage current;

2) The dielectric in the capacitor is generally able to withstand a lower voltage than the AC voltage under DC voltage. This involves the material characteristics, and it is reasonable to use the DC withstand voltage as the rated parameter.