Realtime lighting and "Importance"

Realtime lights also have an Importance setting. Unity will only render (in VRC) 8 lights as full extra pass lights, which places an upper limit on the number of times an individual object can be affected by lights and re-rendered.

Which lights it chooses is based on the Importance setting on the light.

When a light is Important, it's rendered as a realtime light with priority. Important lights can render shadows - either realtime shadows or mixed ones which combine a baked mask with realtime shadows.

When a light is set to Not Important, or the limit is reached, Unity will render the light as a vertex light. Vertex lights are much cheaper than regular lights. However, only 4 vertex lights can be rendered on a single object, and they're typically rendered per-vertex - so they won't look great. More annoying than that, though, is they typically won't show on objects with baked lightmaps, so you can't mix the two.