This question was asked recently: Specificness of Tablespace
There is a nearly identical question that was asked on Stack Overflow 10 years ago here.
I don't think that I could provide a better answer than Justin Cave's excellent answer. The same points that Justin pointed out are still applicable today. I did, however, add a comment on the recent question linking back to the Stack Overflow answer.
I don't think that the question can/should be closed. It doesn't appear to be a duplicate on the DBA site (the closest match that I found on the DBA site is What are the benefits of using a different tablespace for a new user schema?, but even that question isn't exactly a duplicate).
So, what do we do with the question that was just asked?
The best 2 possibilities I could come up with:
1) Do nothing. Future visitors still have the link back to Justin's answer. However, I know that comments can go away...
2) Copy/paste Justin Cave's answer into a Quote block, give him credit, then add the link to the stack overflow question/answer. However, this almost feels like a simple grab for more points (which, despite my low points, I really don't care about the point system).