Hi,
I would suggest using PI for one of its reason of central monitoring, I know connect direct can generates log files, but at times it becomes difficult to open each log file and look for errors when you have so many interface running simultaneously. So for inbound definitely 'yes'. How about outbound, Do you have any outbound interface where you are planning to use connect direct. If yes and if you are also planning to use PI then you will have to invoke connect direct using a CD script. Here the drawback is that PI wont be able to capture any failures if it fails while calling the CD script.
Thanks
Amol