I would put it somewhere more secure than wallet/purse, unless you are forgetting your master password daily. I put mine in a place similar to a hidden folder in a filing cabinet. I haven't forgotten my master password yet, but I know that it's there if I need it.
I would imagine that anyone who is dedicated enough to violate your person to obtain your master password would also not hesitate to violate your house to obtain your master password (in fact, they may do so first).
I think the concern is more that it is a lot easier to accidentally lose a wallet or purse (or have it stolen for unrelated reasons), rather than a targeted attack against your person for the master password.
Well, the copy of it is just for backup purposes most times anyways, so the loss of the copy isn't going to be unrecoverable in most cases. And, as a bonus, you don't have to return home if you do forget it.
And, as I mentioned earlier, we're really quite good at keeping track of wallets and purses in the first case. Losing them is typically (at least in my own experience) a once-in-a-decade event.
