Beta FW has been available for a long time and is part of the development process. It's open and available for both forum users and non forums users as well.
It's up to the users and there choice to load the FW or not. In most cases Beta is the next step for users to try to see if this version helps them in there troubleshooting. And if the Beta doesn't work, users can always revert back from Beta to prior version of FW.
D-Link routers only will show "officially released" firmware through the UI. It is best to download the firmware from the support site and manually upload it.
1.08 is still in BETA and going through the final testing and certification before being an "official release" so it will not show up in the UI.
The fact that a BETA version of firmware is being recommended by D-Link is very concerning. If it is supposed to fix all these issues, then the release notes need to reflect that and it needs to be moved to official release so people can see it in their routers when the check for newest firmware.