What project offers the best UX for microtransactions?

I believe decentralized microtransactions could offer lots of possibilities.
Even though I don’t want it to be owned by Facebook or similar companies, I think Libra offers a great vision on the UX side because it needs to be super easy for the end-users, otherwise it is just another crypto project that’s going nowhere.

So what are the best alternatives to libra that would be:

  • ready to use now
  • scalable and reliable
  • fee-less (or very low fees) and adapted to microtransactions
  • super easy to use/integrate

I’ve heard of Stellar, IOTA, Nano and some other blockchains could theoretically be adapted. But it’s often difficult to distinguish the vision from the corporate website from the reality.

Let say I want to enable users (that know nothing about cryptos) to do micro-transactions on a website, so they need to credit/withdraw their wallet with real money at some time. So a coin you can buy/sell with fiat coin, without having to convert into ETH or BTC.
What’s would be the best project for that use case?

Human greed has killed the dream of fee-less Micro Transactions.
What do you consider low fee?

Something that wouldn’t discourage using it even with micro transactions (like paying 50 cents at the coffee machine).
Having up to 5 cents on this kind of transaction would be reasonable (if it worth it on the other sides, like UX).

Lightning network: https://blog.bitrefill.com/top-11-lightning-network-wallets-bitrefill-328b5465b1b4