I can’t say I’ve tried this but the thought just came to me that generating such trades would be trivial to do monthly now.

In some countries (like Switzerland) you don't have any capital gain tax __unless_ you are a professional investor. What makes you a professional investor? One of the things that can elevate you to that status is the amount of trades you make.

So I am sure this is not viable for many people as buying an ETF counts like 1 trade, but investing the same money in the underlying assets count like 10s of trades.