It can take between 5 and 15 minutes to complete the enhanced verification. You'll receive a text message letting you know it's finished. If you've been waiting for more than 15 minutes, feel free to give us a call and we'll check on things.
Aside from the typical KYC requirements, the most practical reason is that in the event of some problem with your transaction, we need to make sure we can correct it for you, not someone else. By getting just a bit of information from you before a transaction, we can both relax knowing that if something goes wrong mid-transaction (like a loss of network connectivity or a bill jam) we can make it right.