Priming has nothing to do with cleaning. It’s higher octane fuel. If your car Isn’t designed for higher octane fuel it will run like garbage. The whole point of high octane fuel is that it requires a higher temperature to ignite. If your car Isn’t designed for it it’s most likely only going to partially burn the fuel.
No, the main point of high octane fuel is to be resistant to higher compression ratios so it doesn’t pre-detonate. Spark plugs have no issues igniting it.
What op is referring to is additives that are added in by some gas dealers to the high octane fuel to upsell you. “Techron” is one I recall seeing at Chevron IIRC.
High-octane fuels will not burn poorly. It just isn't necessary to increase octane further once the threshold of knocking/self-ignition at the target compression and cylinder temperature is reached.
Plus you missed the point: In many places the premium fuel is the same octane number as regular (e.g. 95), but premium is with additives for <insert vague marketing>.
