No, the point is in crowded places like airports you don't want people zipping around on electric scooters, suitcases or otherwise, running into people - esp elderly.
You've got to have "police" everywhere who need to be trained to identify when someone is going too fast. Who does enforcement? Actual police? You need a lot more police than normal. Airport staff? They're not enforcers. They keep the carts in the right location and bathrooms tidy. But, let's say you can have enforcers. So enforcer says slow down, kid says okayyyyyyy and then goes fast again right out of eye sight. But speed limits on the luggage! No way, so add an on/off button to comply because no one wants to buy only a slow luggage, but you've still got that person who "won't airplane mode".
Repeat offenders? Now you've just confiscated their luggage. That's gonna be good.
In this scenario, electric luggage == actual scooter. You don't ride actual scooters through an airport, but I've seen so many electric luggage scooters.
I admit they're cool af and everytime I see someone on one I'm jelly. They're their own advertising. But they're at an airpot and it's crowded for the speed. I'm already stressed enough - I don't need your kid running into me at speed.
That's pretty manageable when we're walking, but basically impossible when riding a vehicle (at best we stop within the machine's braking distance, including our reaction time until pushing the right button).
Then when a collision occurs, it will be the luggage's hard surface hitting first, compounded with the weight of the rider on it. Compared to person vs person collision, that probably hurts a lot more. Same way it's worse to get hit by a cart than by bumping into someone.
[1] https://www.walmart.com/ip/SE3S-Airwheel-Smart-Rideable-Suit...
And that, dear reader, is where the plan falls apart entirely.
But for real, regulation exists because large groups of people generally can't be expected to act rationally.
Especially tourists, who are the main users of these electric suitcases.
Scooters have no such performance restrictions and as such require licensing, age limits, insurance and all that jazz.
So TL;DR it's just a convenient demarcation between two classes of vehicle performance, that doesn't also limit human only powered bicycles or full scooters.