Not using UE5 here, but in UE4, the left one means “nothing changes about this light at runtime,” so the most things can be pre-baked. The middle one means “light color/intensity may change, but position won’t change,” which means that the light can be somewhat pre-baked, but uses more resources than a fully static light.
Exactly how the lights get rendered is pretty complex, but you can think of “fully static” as “all fully static lights are baked into the same lightmap.” You can think of “fixed but animatable” lights as “each light gets its own lightmap” which means you can separately change the color/brightness of them, and you might even be able to cast dynamic shadows.
That being said, even in UE4, I much prefer the “force no precomputed lighting” mode and just make all lights movable. With Lumen in UE5, that’s kind-of their whole spiel – just make your lights moveable, and things Magically Work (tm.) With the global illumination, key/fill lights will be less necessary for regular scene lighting, and only used for specific scene composition effect.