It is...
Both lifts are not the same, not by a long shot. Your making the same
incorrect assumption that so many on this forum make. Preload lifts change the static height that the truck sits at via preload adjustment - basically, they add compression to the bottom of the spring and that raises the truck. The upper and lower limits that effect ball joint angle are not changed significantly (the Bilstein is slightly longer than the stock strut, so it does change a little, but not enough to be an issue). The strut still stops the suspension in the same places, only the static position is modified.
A spacer lift allows the control arm (and the whole front suspension) to drop much lower than stock, so it significantly changes both the upper and lower limits, and that pinches the ball joint when the suspension droops to full extension.
Sorry, but the way you're envisioning these lifts working is incorrect.