It really comes down to preference.
I'm excited to try oiling my Key West and Paulson chips. We'll see how that works out.
My personal experience with the CPS chips (China clay) is that if we play with them at least twice a month they stay pretty clean/shiny/well oiled. One lady always has her lotion at the table - good grief! I must confess, I use it too sometimes. I find myself wiping them down to keep them from getting too slick. Lotion isn't pure mineral oil, so it's just a mess, NOT recommended!
My craps table Milanos were very dry when we moved. I guess people don't shuffle and play with their chips as much at the craps table. If any of my China clays need oil, it's the Milanos.
Oh, lotion used with my ceramic Tiki Kings turns them into ice cubes sprayed with WD-40.
I don't think I'd ever criticize anyone for oiling chips. If it does nothing other than make you happy, do it. If it adds any other benefit, it's a win win.
If you find yourself thinking, "I'd rather be watching
Gone With The Wind while eating raw kale," you might want to cut back on your chip oiling routine.
I am going to be slightly pedantic here. Saying, "oiling your chips increases longevity," is very different than, "I'm not doing that again, it was a waste of time." The second statement isn't saying the first is untrue, just stating a chosen course and opinion.
If we all could stick our heads up a chemical or mechanical engineer's..... brain and look around, we would be having thoughts similar to, "Hypothesis: Oiling chips decreases wear by adding a barrier layer between the chips. We need to calculate and test for erosion due to solid particle impingement with and without the oil. This includes testing material hardness, fatigue, density, Young modulus, cutting energy and deformation energy based on predicated cyclical forces." I bet you can't wait to hear about delta V (where V is the volume lost) decreasing! Oh, and the physical properties of the chips and how that affects the barrier layer is also greatly interesting. (last sentence said in the MOST sarcastic voice you can imagine)
A scientific look at the argument ends in PDE's and may all be undone by one simple question, "will you do it?" The math club is great at proving 2+2=4, I'm still not joining. I maintain it ultimately comes down to preference, like polishing or treating your leather shoes.
Wow, I'm a long winded oaf.