Of course they are present. They are disinfecting public areas, bringing food to the elderly, and helping construct new hospitals. What they are NOT doing is enforcing law and order.
Contrary to popular belief, there are far more police in this country than National Guard. Even if they were fully mobilized, they couldn't flood all the streets in the country. The image of Soldiers carrying rifles on Main Street would likely lead to more panic. Outside of a major riots and looting, I don't think many want the military enforcing public order.
The National Guard is excellent at logistic operations, establishing communication, coordinating efforts across multiple government agencies, and providing disciplined unskilled labor to fill sandbags, distributing food and water, etc. Specialized units can also do construction, search and rescue, chemical/nuclear response and various other emergency tasks. While the National Guard does have a lot of medical capabilities, most of their medical personnel work in civilian hospitals.