You can configure an OBi202 either from the OBitalk web pages or you can configure it directly on the device. In other words, either way. You should not configure it both ways because the OBitalk web pages will override changes you make directly on the device. OBihai management favors configuring thru the OBitalk web pages because they believe it is easier.
If you configure the OBi202 directly on the device there is a setting where you can disable provisioning from OBiTalk.
Actually it is easier through Obitalk web page as long as you do basic configuration and use one of their pre configured providers and/or are not an IT expert. Certainly setting up Google voice can be done in seconds this way even by an otherwise completely clueless person.