For the little bitty amount of fuel small engines consume . It's cheap insurance against ethanol damage and damage from detonation to use premium non ethanol gasoline. Small high output engines tend to detonate under heavy loads, in hot weather and if adjusted a wee bit lean.
Many so called lubrication failures had nothing to do with lubrication . Instead the hole in the piston , crushed ring lands , broken rings or scuffed cylinder walls was caused by high pressure shock waves from detonation.