Good intuition... magic is still not part of hacking, sorry. ?
I think you didn't really get what is this [value] in the video: "[value]X4"
Just to be sure I say this, but I think you already know that and it's not the problem here. Let's say you search for Dword:
Searching for "[value]X4" means: "find a Dword, containing [value] (not encrypted) xored with the Dword (see nofear following post) 4 bytes after or before (= just the length of the Dword containing [value], so the following/preceding Dword)"
Well if you understand that, you have to know what [value] you want to search for.
I think you were confused because it wasn't maybe the best example. Nofear is searching for an odd thing. He's looking for the number of coins here, not the actual money value you see. So he does "1~9X4" first because he just collected between 1 and 9 coins, and then he searches for "53X4" because he counted the number of coins the arrow of coins he collected was made of, which is exactly 53 coins ^-^.
Why? Because the money is probably not Xor encrypted, and the numbers of coins collected are xor encrypted and can indirectly change money, and/or Nofear just wanted to show another way to hack money that the way you'll first think about, which is directly changing the money.
You second problem is related to the definition of "[value]X4" I wrote, or most probably to the xor encryption itself. Xor operation is reversible: the value which is xored with [value] can be after or before it. In this case it is before. Plus you have to know that [value] xor 0 = [value]. So eventually, in this case, nofear sets the xor key to 0 and then he can simply change the encrypted coins number as if it wasn't encrypted at all!