With their reduced densities and weight per volume of fuel, the other obvious benefit is that an aircraft with any given volume of fuel in the tanks is automatically lighter. And since many airplanes are flown only occasionally and may sit unused for weeks or months, the lighter fuels tend to evaporate away and leave behind fewer deposits such as "varnish" (gasoline components, particularly alkenes and oxygenates slowly polymerize into solids). Aircraft also typically have dual "redundant" ignition systems which are nearly impossible to tune and time to produce identical ignition timing, so using a lighter fuel that's less prone to autoignition is a wise "insurance policy". For the same reasons, those lighter fuels which are better solvents are much less likely to cause any "varnish" or other fouling on the "backup" spark plugs.
With their reduced densities and weight per volume of fuel, the other obvious benefit is that an aircraft with any given volume of fuel in the tanks is automatically lighter. And since many airplanes are flown only occasionally and may sit unused for weeks or months, the lighter fuels tend to evaporate away and leave behind fewer deposits such as "varnish" (gasoline components, particularly alkenes and oxygenates slowly polymerize into solids). Aircraft also typically have dual "redundant" ignition systems which are nearly impossible to tune and time to produce identical ignition timing, so using a lighter fuel that's less prone to autoignition is a wise "insurance policy". For the same reasons, those lighter fuels which are better solvents are much less likely to cause any "varnish" or other fouling on the "backup" spark plugs.