We don't have to agree and I obviously won't change your mind here. Just saying, it's clear based on your comments that this is not an area you have much experience with.
Even with the same physical engine and ECU, there's very real differences that can be made in software calibration to run different grades of fuel. Not just run, but require. 87 to 91 octane may seem like 4 insignifcant potatoes, but it's not. Low grade levels of knock that are undetectable, but may cause longer term issues. It's your perogative. As one that has tuned engines and used tools, logs, and knock headphones, I won't be taking your lead