Why the zero article in "in daily life" and "became pointless talking"?

A Japanese friend sent this:

IDOBATAKAIGI - いどばたかいぎ - 井戸端会議 - Have you ever heard of "IDOBATAKAIGI"? Initially, it meant a short chat among house wives in a daily life. And now it became a pointless talking.

I replied with these corrections:

• "in a daily life" → "in daily life"


• "became a pointless" → "became pointless"

But I'm not sure why. I want to explain the reason we don't use "a" in that context, but we do for "it meant a short chat".