When the Segway was released? It could do this one cool trick: actually exist. Electric bikes and scooters (at least at any sort of scale) were at least ten years off.
There were other factors. Ungodly expensive for what it was, and poor enough range that I questioned whether it could get the six-ish miles from the house to Microsoft's main campus with that WA-520 hill to contend with. Now my Boosted Rev scooter can almost do the 7.5 mile round trip to work, with that same WA-520 hill, and for 1/3rd the price the original Segway was going for.
EDIT: oh, wait a minute, the max speed on the original Segway was like 20kph/12mph, right? Yeah, the Rev would easily make the 15 mile round trip if I were riding it that slowly.
Segways have much better low-speed handling characteristics than bicycles, which makes them safer to intermix with pedestrians: Travelling at a slow amble speed in a crowded environment is extremely difficult on a bicycle, but no big deal for a Segway (or similar)
Now I ride a Onewheel.
The segways itself doesnt make much sense to me though. I dont remember too much about the hype when it was released, but like, I'm still unclear about what it was supposed to be able to do that an electrified scooter or bike couldn't.