I'm not a fan myself but a bumpy wall is easier to put in than a perfectly smooth one. I have a few bits of substandard plastering and the very small snags / gaps / scrapes stick out an absolute mile for me. A bumpy wall might look rubbish but at least imperfections are harder to spot.
On the subject of texture. What is with the US and 'texturing walls'? I don't get it, why would you want a bumpy wall?