What you were told is simply a scare tactic to get you to buy points. While technically correct, that some inventory may only be available via Trust points directly from Trust inventory, we have found that the vast majority of DC reservations come from the MVC Exchange (where weeks from enrolled owners converting to points, Trust Inventory moved to the Exchange, ressie's begotten from II, etc. are comingled). We used to see an occasional week in the 13 month reservation window come directly from the Trust, but I recently booked 3 Hawaii reservations in the 13 month window and all 3 of those came from the MVC Exchange. Trust inventory moves to the Exchange almost immediately upon inventory release...and once in the Exchange, any points can get at them.
So, don't fret.....your enrolled points have 99.9% of the pulling power as Trust points would.
And furthermore, on renting points, most points available for rent are enrolled points like yours. Its rare that I see folks with Trust points renting them out. It does happen, but there are a lot more enrolled points owners out there than there are Trust points owners....and the # of enrolled points owned by each owner are likely also in greater quantity than comparable Trust points owners, so its likely the enrolled owners are the folks that have excess to rent.