This is addressed on the very page though:

> A sovereign US cloud does not address or mitigate the strategic reliance of European businesses and governments on US-based cloud providers.

> Some commentators are therefore calling those attempts “Sovereign-Cloud-Washing” or “EUWashing”.

It's one thing if they require the copy of data, and another thing if the President wakes up in a bad mood and orders deleting all the data. Imagine if the whole computing infrastructure for power plants, public transportation, banks, payment systems, large companies gets deleted in a minute.

You should not host the critical data on other country's servers.

That’s not the goal, it’s about regulatory compliance.

why it should happen?

Intelligence.