As Puck stated:Flags are your friends ;) ;D
When you have a tool available, I'm not sure why you wouldn't want to use it. ???
The "Macro library" was added for purchased X10 designed macros which never took off!
If your looking for working macro samples read the section:
"User-Designed Working Macros
A library of working macros designed by members (post your Working macro here) " (http://www.x10community.com/forums/index.php?board=103.0)
If you need more info on creating your own macros using the SmartMacro plug-in including the product manual check the wiki (http://kbase.x10.com/wiki/Smart_Macros)
If you have a macro already designed and working but not sure how or what conditions to use. Post it along with a detailed description and what your trying to achieve! The likely hood that another user can help you are very high! ;) ;D