It can be a real asset here in Rochester. Check out this URL
RIT - NTID - News - Rochester Area
With the NTID here, Rochester has a diverse large HoH population. When I managed retail near RIT (Rochester Institute of Technology) of which the NTID is part, those with ASL skills were a definite plus. The stores in the Henrietta Town area had many HoH clients and customers.
So IMHO I'd say, although not essential, it is a plus having that skillset.