I can't see it doin any harm, and in the Winter, or variable temp and humidity situations where you may get condensation in your tank, it generally helps by offsetting the watered-down-gas syndrome.
Of course, the Oil Companies right now are doing thier level best to steer folks away from Alcohol in fuel, cause that might lead to Alcohol Fuel...which they do NOT want.
Hell, the only reason cars run on Gasoline anyhow was that in Henry Fords time, Gasoline was just toxic waste, a waste product of kerosene production.
With our HUGE surplus of grain/corn, etc - we could convert easily and efficiently, there isn't really any logical reason to run on gasoline anymore, but they've a monopoly and intent to keep it.
Notice how every time they try to force the Alcohol-in-Gas solution how many...uuuh...petroleum "accidents" suddenly occur to drive the price up ?
But as fer that, no - it's not going to do any harm, might even do some good.