Now that routers are affordable, why should I build a network using Layer 2 switches, which degenerate to broadcasting under poor conditions, and not just use real routing at Layer 3?
Edit: Got some great replies. Let me clarify the question: Of course, at the lowest level, you want to plug your end nodes into a switch, not a router (as demonstrated by AlReece). I'm referring to switches which are used to bridge traffic between segments - that is, switches connected to other switches.