The tab character has been around since 1963. I have so far never in my life had a problem with using "smart tabs"[1][2]. For my purposes (web development), I don't expect that this will ever happen.

I'd be interested to know a real-world, recent example where tabs could have been a problem for someone.

1. http://www.emacswiki.org/emacs/SmartTabs

2. http://vim.wikia.com/wiki/Indent_with_tabs,_align_with_space...