The wave bug isn't an issue for me at all.

The issue is that there is a very slim chance that the alarm will get hushed if people run by the unit repeatedly and the device is mounted in an odd place (like lower on the wall).

"Within 24 hours, Nest Wave will be automatically disabled. You don’t need to do anything and even with this feature disabled, our smoke alarm will continue to work very effectively, monitoring for increased levels of smoke and CO in the home. "

https://nest.com/letter-from-the-ceo/

It's just too risky for them to leave the feature on considering the product is a general public safety device. One death with Nest Protects would be disastrous for the product and the brand.

It's also important for home automation in general to prevent loss of life in these early products. Look at what happened to Tesla and the fires, the media makes small issues with new technology appear to outweigh all of the benefits. The media isn't running a story every hour on the new 1/2 inch plate of titanium which, to me, is extremely awesome, but that's just how press coverage goes right now.