Because your faucet only for Xapo wallets. Set in profile "My wallet from Xapo" to "yes", and faucet shown in list.
Actually this shouldn't be the reason because it pays to faucetbox too.
I just tested it too and got payment to my faucetbox after 1 claim.
yes my faucet also pays to facuetbox !
and i cant change my faucet settings on ifaucet.