I believe the beta servers two (2) functions:
1. To test one's applications against the new software.
2. To help Apple with the development of the beta software.
Apple has made a bug reporter for a reason. If they were so intent on a beta being used only to test one's apps, they would not ask for feedback / reports regarding the software. Also, this is more than a battery life "issue"...it's an actual battery drain that is more excessive than in the past. I've used several iOS beta 1s and I've almost never felt the need to downgrade because of such poor battery life which caused me to recharge more than once per day.
I think we can all agree that betas will have slight battery issues, but it's something worth talking about when it's drain which doesn't even allow you to get past half a day in most cases.