The price is way too high. 21 billion coins, and the ICO is at a penny a coin.
Phone batteries will be an issue. Bandwidth could be an issue - for the cell phone providers. Security will definitely be a concern. Privacy will be an issue to.
I see phone companies taking a stand against Electroneum and similar projects.
Scalability will definitely be an issue if this coin will be used by millions of people.
That said, 24M isn't a small chunk of money. A lot could be done with that money if used properly.
first of all, the circulating supply is less than 6 billion now that the hard cap has been hit. the rest will be available for mining. secondly, phone batteries and bandwidth won't be an issue, as there won't be any REAL mining done on the phone