The above video is a testament to how far phone cameras have progressed. But what a random clutch of subjects and angles to choose in comparing video function of both phones.
Source: 9to5Mac - iPhone 6s vs iPhone SE iSight camera comparison
That's Relonch's tagline for their APS-C sensor iPhone camera add-on. While the copy reads like it came from a hat -- the next level of mobile photography is the smartphone, not an interface that enhances it -- the idea has merit.
Interfaces that work with existing hardware allow greater user freedom- certainly more so than unwieldy beasts, like the Panasonic Lumix CM1, a smartphone with a one-inch sensor and Leica-branded lens.
Relonch's 500$ price point likely will keep it out of the hands of binge purchasers, but its product location as an extension of, not replacement to, your smartphone is a step in the right direction.