There are myriad inexpensive consumer routers available that include wifi functionality, but far fewer freestanding wifi access points (AP.) I surmise that this is because every broadband connected home needs a router and wants a wifi AP, so a converged device is the most affordable approach to this marketplace. Yet in many ways it’s less than ideal.
The fact that your router and wifi access point are in one device makes that device a major possible single point of failure. It dies and your entire network goes down. While merely inconvenient for the kids coming home after school to play World Of Warcraft, it’s a whole different kind of failure if you’re a full-time home office worker who relies on internet access to be effective in your job.