You are just as welcome at the DVC Member Reception. By booking with cash though
DCL instead of points two things will happen:
1) you won't get a DVC lanyard and invitation to the Member Reception in your room. It is listed in the navigator however and if you don't see it ask at the DVC desk up on deck 4 (they'll be happy to give you a lanyard there (if they are still giving them out).
2) you will most likely during the cruise get an info sheet and invitation to the information session about DVC (since they don't know you already own they will target your cabin for one of these info sheets).
The DVC member reception is fun and usually held the first morning of the cruise (our last one was on the Western where we were in port in the afternoon - the Eastern may have it the first afternoon). Either way go and enjoy. Stop by the desk if you have any questions - they love to see members there.
Not every DVC member books on points and they know it. You are still part of the family!