Philips 9@9j with AAA Backup Battery

[MWC] As low tech as it might seem, we have to admit that AAA batteries are really ubiquitous. That’s why the Philips Xenium 9@9j has an AAA slot at its base. This is, to our knowledge, the first cellphone that can support an AAA battery natively that would give it up to three hours of talk time.

It is an interesting idea, but the tradeoff is: added bulk and more limited design options. The 9@9j should be commercialized in April. Do you think that other manufacturers should bother doing it, or do you think that it is not useful and that’s why no-one has done it?