From Neteller Faqs:
Bitcoin is a digital currency that allows you to safely and quickly add funds to your NETELLER Account from any Bitcoin ewallet app.
It’s easy to put money into your NETELLER Account using Bitcoin:
1. Sign in to your NETELLER Account and click on Bitcoin on the Money In page.
2. After you enter the amount that you want to deposit in your account currency, you will be taken to BitPay to complete the transaction.
3. You will be taken back to your NETELLER Account where you can see the funds now available for transfers to merchants or other members.
There is no exchange fee if your NETELLER Account is in Australian or US dollars, Euro, or British Pounds. BitPay may charge a processing fee. Deposits made using Bitcoin are available immediately for transfers to merchants or other members. Money deposited using Bitcoin cannot be withdrawn or accessed using your Net+ Prepaid MasterCard® or your Net+ Virtual Prepaid MasterCard®.
He might not have a verified account to use the feature or simply do not want to use it OR he may use the trades too as a way of getting feedback and trust on the forums while serving his own needs.