> it's very easy to add a TFTP server and configure everything to serve whatever you want.

In your own homelab or in a small company, sure.

But the nice thing about proxyDHCP is that in a larger company, if the network engineering team hands you a subnet to play in that has DHCP forwarding configured in the router already, and you want to do PXE in it, you can just deploy your own proxyDHCP server without any extra red tape.

Or in my case, I just don't like to have configuration for a single service scattered around my network devices if I can avoid it.