Well with the automated GB system it allows the Host a lot of flexibility and easier at doing their job saving them countless hours of back and forth PMs over addresses and what have you.
It will also allow the User a better tracked experience and also less PM times etc. A user can log in and track all the GB he or she is in, etc.
In regards to paying straight away each host again has control and they have the ability to list all the details of their specifics on their item pages.
1) Paying straight away means less people backing out or not fulfilling their commitment which has left many GB Hosts stranded many times before.
However, this isnt to say that a GB Host couldn't throttle their qty to then allow people further time to pay. For example sake, say I have 50 qty to sell I could put up 30 on Go Live date, 10 the next week and 10 the next making it still 3 weeks to pay from when a GB went live etc. So if your host is used to working with you or others in these instances then its not to say the ability isn't still there. fyi.
We are rolling this out in stages and this feature will get better and open to others as time goes on. Give it it's fair shake and time, and the more you dig into it the more I think you will enjoy it.