I don't know how it works, but it seems impossible to get some Satoshi with a limited battery supply.
, but so far is cool, maybe next in the metaverse world it could be happening in our dreams.
It seems that this is a little off topic or it is better to discuss it in mining board, but I do not think that it is a battery because the S9 mining tool works on AC, so you need a battery and a converter. If we ignore the noise and the cooling mechanism, all these things make that mining bag movable NOT portable.
As for the return, it will definitely not be a solo mining, but within mining pool. it will have a return more than some Satoshis.
I remember seeing it before, it's nothing new in EXPO 2023.