I agree, but the thing is, for social work, this is to distinguish people who literally sleep outside of houses due to poverty from the people who currently do not have a stable place they live and are couch surfing with friends and family for an undetermined amount of time before they move into a more stable accommodation they are responsible for.
As in, you can be homeless for a few months while you are moving between cities, but end up in an apartment after that, which is drastically different to having lost all your support networks and searching for a safe place to sleep each night in a city not knowing when you will get to have a fixed address and a bed to sleep in.
That's the social work distinction between being in the broader category of "homeless" and "sleeping rough".
Also, some homeless people are in the system and living out of shelters of various kinds, wheras others are outside the system and living on the street.