Yes that particular gear is, but the logic behind it not necessarily. It shows that even if the Jamo sub will not add much if used on its own, it will be useful once you add another and more powerful sub. Such bigger subs do not necessarily cost an arm and a leg either. For now, you already have decent enough electronics (in fact, you even have two amplifiers), so you should spend your entire budget on the best available speakers within your budget.
And since you mention a tiled floor, think about some carpet if you want to avoid the swimming pool sound.