For example, if AMC is $1 and GME is $1, instead of buying the stocks directly we pay you $1.001 for both and you basically hold the stock for us. If we sell you sell the stock on our behalf and give us the cash and handle the tax forms.
However, if we wanted more GME and GME's price fell in half to $0.50 and AMC's price doubled, the new prices are GME: $0.50 and AMC: $2. It would be awesome if we could "trade" our AMC for 4 more GME without having to pay the gains on the $1 we earned on AMC.
Obviously you can only delay so much under this scheme, but I'd be willing to pay a slight commission if you could facilitate a scheme legally to minimize the tax burden of trading.
Like Robinhood making commission-free trades mainstream, if you can popularize this that would be good - sometimes if you're holding a very popular bubble stock you don't necessary want to cash out for cash and want to directly trade it for another stock without selling. Unfortunately what I'm describing would require crazy volume to be worth the implementation effort, but it's worth thinking about!