Well whats the other alternatives? Sending images to devices on a shared network, or having a server in your house/phone which receives the images. All of them are quite unpractical, most people don't know how to setup a server in their home, heck most people won't know how to even forward ports (hence UPNP in CPE/SOHO routers).

Running a server on your mobile device isn't an option on all platforms, many cellular ISP's don't provide you with a "legal" internet IP but rather use NAT, and running server software on mobile phones is probably a bigger security risk than this.

And while some might say well they could've used dropbox or any other similar storage yes they could, but no one in their right mind would ever design a product which relies on a 3rd party like that since that 3rd party can (and they often do) change the TOS or scrap the service you rely on completely.

This device isn't for people who are paranoid about their security and privacy, you don't put a device which takes a picture of anyone who enters your house if you worry about privacy in the first place. This device is for people who want convenience and as long as it's cheaper than an intercom with a camera in it or is much easier to use it's fine. This is actually quite nice solution for various apartment / condo complexes, you can buz a delivery guy into the hallway when you out and about if they hook it into the buzzer.