That seems to be the beauty of it: you can chose. One way sync O>GC or GC>O or two way sync, and which Calendars so if you want everything in a single one -- go for it.
I'm syncing O to GC it a GC "work calendar" to keep things separate from my personal calendar.
It's been doing exactly want I want, so far. Of course, it runs locally so only works while my computer is on. If I add something to my Outlook Calendar from my phone, it's not synced to GC if my computer is off (sleep mode), but I can live with that limitation (I've been living with having to unpublish and republish to get updates for months now).