Existing payment methods, paypal, google pay etc, have been absolutely crucial for internet payments, but the micro in the word never ends.

If there are internet payments with a minimum payment of 1 cent, then we need payments of 0.1 cents. If that's achieved, then we need 0.01 cents minimum transaction. The micro in the transaction always needs to be smaller (and faster).

Free competition (or perfect competition) over a well defined landscape, internet protocols that is, has proven to always deliver better quality goods and lower price. Money derived from governments is far, far from free competition, let alone well defined internet protocols, and there is a point in which existing payment methods get stuck and cannot deliver smaller transactions.

I don't personally know where and when that point is, but if i have to guess, existing payment methods have reached that minimum point for at least a decade. In other words, their transactions minimums have to be high enough for them to make a profit. Yes, they can implement microtransactions, but they will not be profitable.