No doubt both are useful. Both are good quality setups. I've always wished there was a truly good way to have a red dot and a scope on the same rifle. The two you picked are good choices for a combined setup. Maybe I'm biased because I have 2 Nikon ProStaff 3-9X40 scopes I'm using. Mine are earlier models than the P223. I really like those scopes. They are very clear and gather light really well for their price. They aren't Night Force or anything but they do pretty well. I have a Vortex Strikefire II on my AR and I've been very happy with it. I have been tempted to put a Primary Arms Advanced red dot on it because of battery life. I have that sight on a Kel-Tec KSG shotgun but I'm thinking of selling that gun. It's a great weapon but I don't really expect to be in a trench war any time soon. It's a genuine example of overkill IMO. It's fun to have but not really practical. I can't carry it in the truck loaded in my state or that might be a different story.

But your post is correct. Scopes and red dots both have their uses. If I had everything I wanted on one firearm it would likely weigh 40 lb.s though.