That "in practice" makes it sound like macros are so hard to understand that they're not worth using in real applications, which is definitely not true. Between the facts that (a) one uses them in deliberately restricted ways, (b) one gets increasingly familiar with them, and (c) they are are, token for token, way more powerful than ordinary code, macros end up being used a lot.
Certainly having experience with Lisp/Scheme will make it easier to deal with Macros.
As a "newbie" to Scheme, (well, actually what I played with was Arc, but I think it belongs to the Scheme family) I was able to write a few macros, and seeing them work in action was very nice indeed.
The tricky part is maintaining the macros or changing their behavior. It's like that saying goes: if you write code as cleverly as you can, you are not smart enough to debug it, because debugging is twice as hard.
