Let me quote what one site says what this command does:
In other words, it basically enforces whatever executable file set with that special SetUID to run as the owner's ID instead of the user, which is basically what you want ping to do.
And if you're worry about someone creating new socket types, I wouldn't worry about it with ping since all pinging does is, you know, ping if something is alive at the other end. Technically speaking, the ping's permissions should be set that way since ping doesn't do anything other then, you know, ping.