Good question, Spencer! My reasoning is that I don’t actually want *all* of my traffic to go out over the VPN: I have a few work-related tasks (over SSH) that require that I use my home IP address, for example, plus I sometimes use a different VPN for other purposes. And… I had a spare Pi just lying around, but I’m not certain which if any of my routers are meaningfully flashable (one certainly is [and, in fact, has VPN client support as standard IIRC], the other’s a bit retro and low-powered).

Finally, I wanted some experience in setting up a Pi as an access point anyway, because I’ve got a project in mind for the near future that involves using Raspberry Pis as WiFi captive portals as part of a geocaching-style puzzle game (that’s basically the same kind of configuration as this, but without the VPN bit: these puzzle-based captive portals won’t actually provide real Internet access to anybody).