The trouble with any such footage is that it can be used against you ("as the the defendant's own records show, they were present in the murder area") but they generally won't extricate you when produced by you, since you clearly have a motivation to use it selectively. So you showing a picture of yourself reading a book during what you claim is the murder night is not an alibi, because it could have been produced at any other time, and you will have a massive uphill battle in the court to authenticate that image, and risk even sink you further if you fail ("the defendant even prepared an alibi").
The only way I would accept a commercial product performing this always-on archiving is if:
1. It's encrypted by default with a strong key that can't be subpoenaed or circumvented.
2. The encoder generates its own random key upon installation which I don't know (recoding effectively random, undecodable data), and I then have to manually change the key if I expect to ever read the recording.
Number 1 allows me to review and footage and only release it if it's in my interest, and number 2 affords me plausible deniability, if I don't release the key I can claim I did not know you need to set it manually.
Sure, as long as you are the only nerd doing this, you don't need this complex setup, and you will probably get to use it the unencrypted footage only in your favor. But when it becomes widely accepted as a social norm (say, everyone wearing Google glasses), you can expect law enforcement will become aware of it as a cheap source of self-incriminatory evidence.