LOL , Would you buy a brand new Blu-Ray player then link up a fugly old DVD-player to it with all the extra leads just so you had the correct functions that the Blu-Ray player should have had to start with?
Well that's what the pros do - they break out each device so it can do what it's designed for.
A consumer-level wireless router is really a router, a switch and a wireless AP all in one. But as the expression goes "jack of all trades, master of none." There are compromises in some parts of the design which make the whole unit weaker.
There's are two excellent articles right here on this site:
How to Improve Network Performance, Part 1
How to Improve Network Performance, Part 2
These articles advocate breaking these all-in-one units apart and choosing the best dedicated devices to perform one job only. A lot of very expensive commercial routers have few ports, really all that's required is WAN-LAN. That's why this Ubiquiti router has few ports, it's intended for low-level commercial applications where the end user would likely use a switch. The router does its job, then the switches do
their job. Commercial networks even break down a router further and separate out its firewall functions using something like this:
https://www.barracuda.com/products
I just got an ASUS RT-N66U. But if you take a look at the router charts, this Ubiquiti EdgeRouter Lite beats it for LAN-WAN simultaneous throughput. However the RT-N66U has some of the of the best 802.11n wireless performance ever tested on this site. Wouldn't it be better to use the EdgeRouter as a router and the RT-N66U as a wireless AP? The combo would be faster.
Not that I need all that speed, I mean the RT-N66U has more than I'll ever need, but the Ubiquiti is better as a router. Its firmware is much more flexible and adaptable. I used to have a Linksys WRT54GL with DD-WRT and the router functions were much better than the RT-N66U. Wireless, not so much...
So another advantage to this approach is that if something better comes along, you can swap out that one component.