Alcohols have a great affinity for moisture. Once they exceed their capacity to absorb it, then you have problems. There are a couple of threads here where people have had problems with their REx where, through extended storage, the fuel turned to gell and the vehicle wouldn't run. One person I trust runs a small engine repair facility...one of his biggest jobs is cleaning out fuel systems from old fuel that contained ethanol. Most of those do not have the same sealed, pressurized systems, but why risk it? Also, the octane (highly volatile components) tend to evaporate over time, lowering the octane level. Again, the sealed, pressurized system should help, but where does that extra air to pressurize the system come from...outside, where the air does contain some moisture. Avoid all of those potential problems by using the fuel once in awhile and refill with fresh. The more full, less air needed to pressurize the tank, longer life.
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)