You may think 3 ply napkins would be a better napkin in all circumstances but that may not be true. Three ply napkins tend to be thicker and stiffer while two ply napkins tend to be softer and more yielding.
If you are using your napkins for beverages that may have a high amount of condensation, then 3 ply may be a better choice because they will absorb more, although drink coasters may actually be a better alternative for this situation. If you are using the napkins to help your guests stay clean and tidy on both their hands and face, then 2 ply would be more comfortable.
We have always stocked 3 ply napkins in the past because we wanted to present a product for the worst case scenario, however in spring 2023 we switched to a 2 ply napkin because we can get a better quality product. Also, 2ply napkins ship for less, store for less, cost less (we avoid raising prices), and produce less refuse volume.