Her point is a good one. When they reconvene, Gaeta gives Martha's ensemble an approving once-over. His own outfit—loose pants and a white button-up shirt—is the kind of casual that takes a certain amount of effort to achieve.
"Ready. You really flatter that dress, you know." Which is true, but she looks enough like Dee on the nights when they would go dancing and drinking before the worlds went to hell to make the observation bittersweet.