You are correct, this move, if true, will be for optics only at best and more likely to handle the logistics of caring for them as the caravan crosses the border. Trump is willing to do what is necessary to stop the invasion, but federal law and the courts will stop him.
President Trump needs to learn that with the courts, it’s more effective to apologize than to ask permission. Respond so strongly and so surprisingly and so outrageously to the invasion that Congress , courts, and the Mexicans, and the left are left sputtering and hurling threts amd injunctions after the fact uf the repulsion of the horde.