I don't know how they will get around the divisibility aspect. Like you point out, there will be a lot of $50 transactions. Larger purchases will potentially be broken down into sub-purchases. Left-rear-tyre, left-windscreen-wiper etc etc.
You could also realise all your gains tax-free by buying and reselling $50 items. Like NFTs.
That works fine on minute level, but once you start dealing with big amounts it just isn't doable.