I'd be really surprised if that happens (if we get someone from there, it will be Finbogasson), but you're being a bit harsh.
1. We can pay him more than AZ
2. We (a) haven't had a real chance to develop talent and (b) he'll probably be with us for about a season if a move goes through, so it's irrelevant.
3. The EPL loves Celtic. We're even able to give them shitty guys and they keep coming back for more (see Jos Hooiveld and Ki)
4. He'll get more exposure in Scotland.
5. The SPFL will be a perfect warm up for Ghana