Yes, easier for them to collect unemployment. If they were still on staff but working no shifts then the wouldn't be able to collect unemployment. Better getting some money than no money. There was actually another thread about this.
For full service restaurants, esp independently owned. The staff become like a family. When I worked in restaurants during college, my initial social group was dorm mates eventually moving off campus into apartments. However, my social group turned into coworkers at the restaurants. After work we could go to bars and bottle clubs (after the bars closed). Hit the beach take a vacation together.
At the end of this, if a staff member wants to come back, they most likelywould get preference. Even if it is just because they don't need to be trained on the restaurant's systems.