Roma's transfer embargo, what's the point?

If they are allowed to sign Taddei, Nonda and Kuffour are allowed to move this season before July 1st and then next season they have to wait until after July 1st?

They could still offer contracts before the embargo is lifted so it wouldn't even cause them a penalty trying to pick up next years free transfers.

Surely for the penalty is to have any impact it should exclude them from a summer of buying, there books should contain no new players registered at the club for the new season.