Adobe RGB was designed so that colours a printing press can produce could also be edited on screen, and it reaches further into greens and cyans than sRGB does. Many cameras offer it beside sRGB, and studios that produce for print and web from the same shoot often work in it.
The trouble starts when an Adobe RGB file meets software that ignores or strips its profile. The numbers are then read as sRGB, and the picture looks pale: greens go grey, reds lose depth and skin looks flat. A listing that mixes Adobe RGB and sRGB images shows one product in two shades. The camera's colour space setting and the profile name in the file information reveal which space a file uses.
A few specifications written for retail suppliers ask for Adobe RGB, while most channels expect sRGB or convert to it, so the target is set by the channel and not by habit. A studio master in Adobe RGB is fine; each upload is a converted copy. For photos meant only for the web, setting the camera to sRGB removes the step, and for raw files the space is chosen at export.