There are at least two catches with micropayment ideas. One is transaction costs. The other is taxation.
If person in country X is accepting payments (micro or regular) directly from customers/donors in country Y they are then running an international business. That can have income tax, sale tax, VAT, and probably other tax collecting and reporting requirements in one or both countries.
It's a big can of worms you probably don't want to deal with unless you are making significant money from Y. Multiply all that by the number of different countries you get paid from.
The best way to fix the transaction fee problem is probably to use an intermediary. For micropayments people (payers and payees) have accounts at the intermediary. Payers preload their account with a payment large enough that the transaction fees are only a tiny percentage, then can direct how that money is distributed. On the payee side the intermediary waits until the payer has received enough to be able to do a transfer to the payees bank account without transaction fees eating too much.
The intermediary can also fix the tax problem. The way that works is that the intermediary operates as a legal entity in both country X and Y. Payers interact solely with the legal entity in their country, and payees interact solely with the legal entity in their country. Payers and payees then only have to deal with their own country's tax system.
The problem here is who should run the intermediary service? I doubt people will be able to agree on that. What we probably need is a system where there can be multiple intermediary services, but the services talk to each other so if say I want to donate to project Foo and Foo and I use different services I tell mine to send Foo a micropayment and my service and Foo's service make that happen.
This could work similar to the way peering works on the internet backbone.