Oh dear, the great debate concerning premium fuels. Dare I comment? Of course I will. I think there are two very good reasons why you might want to buy premium fuel, no, maybe 3?
So lets get the "maybe 3" out of the way first. It is to avoid the reported damage an E10 (or greater) fuel might do to your small engined machine. (lawn mower, cultivator, etc. Part of my hobby activities includes messing about with vintage horticultural machinery. Many of them use diaphragms in their carbs and fuel hoses which can be damaged by ethanol. They seem to survive the 5% but instructions have been issued by manufacturers not to run them on E10 for that reason so I run mine on E5. If you have a newer machine you don't need to worry, it'll be fine.
Second is that if you have an engine management system, as many modern cars do, which can take advantage of the higher octane rated premium fuel, then you will likely see a small improvement in performance - acceleration and economy. It's probably not going to be earth shattering and may not be enough to offset the extra cost of using the fuel - depends on the car.
Thirdly I think there is a very good argument to be made for using it in anything with one of these small direct injection petrol engines where I think the added RON will reduce the tendency to LSPI (Google it if you don't know what it is. Makes a very interesting read). Here's something to start you off :
https://www.oronite.com/about/news-activities/low-speed-pre-ignition.html