Can't addresses be credited and debited in the same block? If not, why?

[EhVedadoOAnonimato]

I've just been told that a given address cannot be credited and debited in the same block. That any output filling an address must be at least one block behind of any input spending it.

If this is true, why is it such? What's the point of such limitation?

Thanks.

[EhVedadoOAnonimato]

Never mind, already got a reply: https://bitcointalk.org/index.php?topic=78171.msg950058#msg950058