In answer to the original question, I've seen a lot less deserving challengers. Why Wilder wanted him as a voluntary , I'm not sure. Yes, he has a decent ex pat following there, but if that's the best moneymaker he can get in between mandatories , then he needs to get over to the UK Fast. He'd make more money taking on someone over here.
I'd be really curious to see if the likes of Haye and Joshua or even Joe Parker would risk fighting Szpilka . I thought he did really well till he got KTFO.