Is sizing fonts using “em” still relevant?

Question

Those of you who use em when sizing fonts will know that they can be a headache when dealing with nested elements, and having to make the px -> em

Answer 1

Although allowed, I've always felt it's a little nonsensical to size your fonts using em. When used for font sizing, it's a relative measure, and I think it just adds confusion to your CSS. If you really mean to give your font a size relative to it's parent font size, use percents. (font-size: 0.8em is equivalent to font-size: 80%, but the percent is more sensical.)

Otherwise use one of the absolute units. Browsers handle and scale them fine now.