Danno Ferrin asks the question, "Why would someone writing a GUI in Groovy need a Matisse-like GUI Builder"? The logic in the answer to the question is quite simple but effective. He uses the simpleness of Geertjan’s example to further dive home his point.
Geertjan's sample is deceptively simple. [snip] What if you are doing an address form where the labels are all left aligned and the text fields all need to fill the same width (which is for most to the right edge of the form), except for the checkbox on row 4 for suite number and the text field it enables below it
The logical conclusion is that Matisse is perfectly suited to helping developers work with these types of layout requirements.