“Street Food” has generally referred to prepared food items ready for immediate consumption sold on the street or in a public space from a food cart, food truck or similar moveable station. The connotation was cheaper fast food.
Today, “street food” is a unique, trendy selling point. There is Piada Italian Street Food that brands its entire restaurant chain this way. It’s the same with Tortilla Mexican Street Food in Columbus, Ohio. At Blue Agave in Springdale, Ohio, a local Mexican Restaurant that I frequent, they have Street Tacos on the menu. Quan Hapa in Over-the-Rhine in Cincinnati advertises itself as Asian Street Food. The whole notion of street food has changed to a more favorable connotation. It is nostalgic, bringing together the idea of unique, freshly-cooked food served in a social setting.
Fast food too has evolved with the idea of “fast casual”. This is a whole new category between fast food and casual dining. It seems “fast food” still has a poor connotation for quality, making it appear that the move toward “street food” or “fast casual” may just be a way to avoid being labelled “fast food”. Whatever the ‘label’, I have to say I love Piada, Tortillas, Blue Agave, Quan Hapa, and eating at food trucks. But I also love The Waffle House, so maybe you have to consider the source.