I do not see the situation as a 'pitfall', but rather a great opportunity to pick up X3 at a good price.
Yes, there will be either another maintenance release - which would be free - OR there will be a new version release, in which case you will still have X3e.
The advantages are in having it now, IF there are features you wish to have access to at this point.
The disadvantage - if it is that - is really down to whatever the difference in upgrade price is between your current release to the new release, and the difference in upgrade price from X3e to the new release.
If that total difference between the two upgrade paths is maybe $50 or so, then if I were in your shoes I would skip a couple of pizza nights and go ahead and upgrade now to X3e now.
This same question comes up literally every year at around this time, and the conditions remain the same, except that in this case, X3e is considered by most accounts to be a stellar version, perhaps as good or better than 8.5.3 was.
I think it would be money well spent - more invested really, in a tremendous release that you could jump into right now.
Bob Bone