Moped seats are for sitting, bike seats are for pedaling.

They're not worse, they're different because they need to be.

Are people going to pedal on these things? Mopeds could also be pedalled if stalled -unlike scooters. I mean, sure, I know their form factor is that of a bike --but its locomotion is more similar to that of a e-moped. Unfortunately with very lousy seats. At moped and these ebike speeds you want better seating.

Yes. There are e-bikes that look like motorcycles or mopeds that can be pedaled, but are uncomfortable, and there are e-bikes that look vespa style scooters that have pedals but it's completely impractical to pedal them - the pedal operation is there to qualify under specific requirements to be classified as an e-bike.