There is no way a mining can be done in the phone device, it's absolutely impossible, the hardwares used have greater GPU space and with good efficiency compared to the ones in phone device even in PC, Pi network teams are sort of scammers trying harder to get access to peoples storage files and get rid of all their secret keys, who knows if the recent hack of wallet is operated by pi network hired scammers. I may be wrong anyway.
They might be scammers (or not) I wouldn't know that but they are great in marketing, that is their positive. I know one person who has absolutely nothing to do with crypto and never invested into anything, including bitcoin, asked me about Pi for example, that was the moment I realized I may not invest into this, but it will grow, maybe in price or maybe in user numbers but I know that it will grow.
After all, if a person who never invested even into bitcoin suddenly gets an interest towards PI that means that project team must be doing something right, that seems like a possible deal. I am not saying it will go above everything else, but a possible increase could happen if they keep going like this. I also think that it could turn into something myself as well, it is not an empty deal, but I just think marketing is done better than the actual work.