For my part, I think the definitions in The Catch are bad. It should be common/uncommon/rare rather than common/rare/all-but-nonexistent. Even the example given is bad: after all, having as a Catch an item that voids all Catches anyway is hardly a Catch, is it? I think the description should be more like this (and this description is consistent with the costs given for sample characters):
* If the Catch is bypassed by something that anyone could reasonably get access to, but usually doesn’t carry on them (like cold iron), you get a +2. If it is bypassed by something that anyone could get access to but that is uncommon or difficult to find or obtain or difficult to use as a weapon (like holy items), you get a +1. If it is bypassed by something that is very rare and/or difficult/expensive to obtain or restricted to a special class of people or not generally useable as a weapon (like True Magic or a four-leaf clover), you get nothing.
* If almost anyone with an awareness of the supernatural can identify you and knows about your Catch or could easily find out (like from the Paranet, or Bram Stoker’s Dracula if you’re a Black Court vampire), you get a +2. If identifying your breed or knowledge of the Catch requires access to specific research material that could be restricted (like a wizard’s library), you get a +1. If knowledge of the Catch requires knowing you personally to learn about it (like the effect of Judas’ Noose on Nicodemus), you get nothing.
Note that I've also added factors involving ease of weaponizing a Catch, and identifying you as a member of a group that has a Catch. I think this plays a roll in things like sunlight (easy to come by and free, but harder to use as a weapon and useless at night), the iron alergy of Fae (something that is wide knowledge, but most Fae aren't necessarily obviously Fae unless you know what to look for), etc.
Other useful clarifications would include such things as what to do with the presence of non-weapon Catches. The rules mention that the presence of such things might be a good excuse for a compel, but this seems rather weak with respect to such things as sunlight and vampires. Presence of a Catch should also disable Recovery powers while 'close enough', and direct contact should make use of environmental damage rules.