I'd say it's worth it if only costs you rods, time and beer. I'm in favor of saving every anvil possible.
My caveat would be that you take the time to thoroughly research anvil welding repair. It would likely take a few days to read through the different welding rods used and why. What pre-heat temps and why. Etc.

Don't think there would be enough face left if you ground/milled it. You might think of saving this anvil *for* texturing stock and come up with some designs that make use of it---like the fellow who forged a picture frame on a granite cobblestone to get the texture he wanted.

Otherwise it's hours of welding/grinding.