I disagree, I know many people who use @ to address someone... and its easy to see...
I detect your 2nd reason to be a +0 in supporting your conclusion, of "I disagree."
And your 1st reason doesn't seem to be much weight. Taking a sample of a population doesn't tell you much.
Really want someones attention? Try CTRL+R. A little annoying though.
If some people have nick highlighters for $me separated by spaces, ($chr(32)), then saying their nick in $+ color won't trigger it.