IMHO it's about the torque curve. Single speed is possible, reverse is a non-issue.
Electric torque is flat to a 'knee' where is starts to drop off, so if it's geared to only use a limited RPM range you won't hit a wall. But,
per Jack Rikard, a single speed motor will need twice the power at lower RPMs.
Hence why I'm hoarding a 68hp electric to replace a 36hp gas engine.