A truly high grade tape will demonstrate its differences mostly in the quality of the image recorded. Extra high grade tape coatings are generally superior in noise immunity and lower in dropouts.
This means that you get a better recording, and you’ll get a better second and third generation copy. Several manufacturers have indicated on their packaging that they have done things to also provide greater longevity, but this is a claim that would be difficult to prove or disprove.
For especially valuable recordings, use a high grade tape; but remember that there is no standardization and no requirements that prevent anyone from naming a product “extra high grade.” Buy a tape with a brand you trust.