Guilty here, but have been doing so for so long that it's largely muscle memory at this point and the original rationale has been lost. In mitigation, it certainly used to be the case that you were likely to come across a broad variety of Unixy flavours and hence using highly conservative scripting constructs made sense; then after a while these become second nature, and unless they cause actual problems they just stay in the mental toolkit.
When I started off in the UNIX world, the shop had a collection of AIX, SunOS, Solaris, HP/UX and Digital UNIX. the x-hack was standard form and I spent a few years fixing errors with the x-hack (or converting the scripts to Perl).
It is just second nature to use the x-hack in if's and case statements on this point. I have to try really hard to NOT use it. Of course, the folks with less gray in their hair and often confused by it, referring to it a "Olde Unix."
I have approved plenty of PRs with the comment, "Updating mek's Olde Unix syntax."
