The obvious problem with smartphone voting is that it's hard to combine with voter secrecy. An abusive spouse or someone bribing the voter could demand to see what vote was cast.
And if anyone can make up a reason to doubt the outcome of the election, it will fail it's objective: Peaceful transfer of power.
The usual way to try to solve this is the ability to override previously cast votes, in secret. But the combination of that and the ability for all interested parties to independently verify the count is not trivial. But not impossible either, much has been written on the subject since e-voting was all the rage in the 90s. One would do good to study this work before designing yet another voting system.
And if anyone can make up a reason to doubt the outcome of the election, it will fail it's objective: Peaceful transfer of power.
The usual way to try to solve this is the ability to override previously cast votes, in secret. But the combination of that and the ability for all interested parties to independently verify the count is not trivial. But not impossible either, much has been written on the subject since e-voting was all the rage in the 90s. One would do good to study this work before designing yet another voting system.