Yeah that is true, the brick texture should be seamless itself.
However the grouts help a little with that and it's a lot easier to make a standard texture seamless then to mess around with an already finished poorly made brick texture.
If you make brick textures this way, it's also nicer to make the overlayed pattern both provide highlights and shadows (instead of just shadows -- with multiply), and try other layer modes, to keep the colours fresh. Also, I'd suggest cutting up the texture layer (or working with layer masks) to create at least some separate bricks. If the texture behind the pattern is continuous over all the bricks, there's no real illusion that they are individual units.