Those speeds would be under ideal conditions, like sitting on land on a clear day with no weather.
It’s not about the raw speed honestly, but the machine latency and stability of the signal. Traditional GEO satellites need a pretty steady platform to maintain connection. The mobile capable dishes are usually less capable than fixed position ones because they need to be less directional to maintain a signal while moving. But in say rougher seas, the movement will be vastly different than a boat just sitting on a lake.
Starlink can compensate for this better because it’s designed to utilize multiple lower satellites simultaneously in view and a more omni-directional dish, alongside a signal that only needs to go to LEO. The difference between LEO and GEO or its is absolutely massive. The Starlink satellite constellation operates between 1/30 and 1/105 the distance of traditional GEO satellites. This means a latency of 25-35ms since they are so much lower. Lower latency will mean lower packet loss from instability which means higher throughout.
For a real world use case, look at the SpaceX landing ships. They originally used traditional GEO satellites for those video streams, and the motion and vibration from the rocket getting near caused total signal loss. Often signal loss for a white a while after the lending was over because the ship was still moving too much. After they switched to Starlink, I think I can remember maybe twice at the beginning where the signal cut for a second or so, and once they had a few launches to provide more consistent coverage and satellite redundancy, I can’t even remember the last time we lost a signal during a landing.
Real time video streams are essentially the worst use case for traditional satellite communication, and the differences between the network types of night and day.
Ukrainians don’t run the US banking and entertainment industries. They can hold them hostage and bring the country to its knees if they wanted to.