Duplicate add of tag components is allowed, but what about regular ones?

Hi

Why we are allowed to add tag components twice without an error?
Why we are not allowed to do the same with regular components?

 

If you set a tag twice, the result will be the same. Therefor duplicate tag components don't change anything.
If you set a regular component twice, which values would it use? New one or old one? I think there's more work involved.

If duplicate component data error was removed, then what would be the difference between AddComponentData and SetComponentData ? Personally, the duplicate component error helped me optimize code in several cases, where I was mindlessly adding components multiple times.