'wireless routers' usually work fine as an access point + Ethernet switch when you disable dhcpd and don't use the wan port (nice ones let you use the wan port as another lan port). They're usually cheaper than a dedicated access point too.
What's the advantage of disabling dhcpd?
Well, he's talking about access points. You don't want multiple DHCP servers in your network.
I think OPs point is that he's already got a router running DHCP on the network, but if you disable all the router-like services on a second device you can use it as a dedicated access point.