Amazingly Windows and Mac are widely used...it probably has nothing to do with their use of windows over text commands.
Not everyone looking at scripts on this site is a scripter, many are just regular mIRC users who want to find scripts to make things easier or perform cool functions they wouldn't know how to write on their own.
/scon -a isn't exactly common knowledge, so this dialog makes global actions possible for those who wouldn't otherwise know how to do them.