Sounds a bit similar to Spain, where .com.es used to be available for foreign registrants but not .es proper (but that was quite a while ago) ; since the restrictions on .es proper were lifted, .com.es has not been seen or used a lot anymore although it still exists of course and you see it pop up now and then.
I assume the same fate will happen with .com.pt once .pt will become widely available. From my Portuguese colleagues I can only conclude they think in terms of .com and .pt, but rarely .com.pt ... Cannot recall having seen it in any advertisement neither.
Maybe very good keywords in Portuguese will still be valuable though, regardless of .pt proper's status.