No problem,
handleman.
True, you can monitor events with macros. However, macros are not compiled and require more resources to run. Leave a macro running for an extended period and it almost certainly will affect performance. This would be especially true if the script failed to properly release objects.
Because macros run slower, it is possible for them to fail to register events. I have seen this firsthand. Even compiled programs can miss events, but it happens much more with macros.
As inferred above, one advantage of an addin is that it is compiled, and thus runs faster. It can run processes on an independent thread, relieving "pressure" on SW processes.
Another significant advantage is that they are triggered automatically with SW startup (as long as they are activated). No "forgetting". Addins also allow for adding menu items and toolbars.
If you want to, you can create a macro (VBA) and then cnvert it to an addin in VB6. I have a project to do exactly that on my website. You can write your ode, then find a local programmer to turn it into an addin with a few simple steps.
I could be the world's greatest underachiever, if I could just learn to apply myself.
-SolidWorks API VB programming help