I actually misnamed this topic because I thought it broke with just files at first, then halfway through I relized it breaks with anything after the wildcard. A mod can ammend it if they wish
If I had to guess why... (I love writing these posts)
It's probably because the Detect lines perform a simple conditional statement to establish the presence of an application. If the conditional was performed on items in directories further down the directory tree from the point of the wildcard; a recursive operation would be required. As all the Detect entries are processed on CCleaner's initial application load event, the time consuming nature of recursive scanning would have severe performance consequences.