Lyft/Uber cars are reliable and guaranteed to come to your door in 5-10 minutes. With these scooters you have to hope that there's one around and walk a few blocks to pick it up.
In NYC people use citi bikes for their daily commute because most of us don't have space for a bike and locking one on the street is a bad idea. I see people with regular scooters, skateboards and boosted boards at coffee shops and on the subway all the time so an electric scooter shouldn't be that big of an issue.
It's not whether it would be an issue or not, it's whether I want to carry it around.
Right now these services are a novelty so a lot of people use them but they don't really pass the toothbrush test. Their top users will do the math at some point and end up buying a scooter to use for their daily commute.
The bike hire system in Copenhagen is underused -- most of the business is from tourists rather than locals, since most locals own a bicycle, or quickly buy one.
If the scooters become popular, the risk of theft will drop significantly, and then there's not much reason not to own one.
Don't underestimate the power of convenience.
Professionals that don't want to arrive at work all sweaty because it's a hot day.
People who need to be somewhere in 5-10 minutes and don't want to jog.
People who generally value their time more than the cost of the ride.
Random trips create more random trips, they complement each other. When everybody is tied to their personal vehicle, the return leg will always be on the same mode. One-way friendly TaaS makes all other forms of one-way friendly transportation now attractive, relative to personal vehicle use.
This, if you are using a scooter more than once a day renting for $1.75 a ride simply does not make any financial sense.