Libra is still a problem. They start with a basket of USD + Yen + EURs to start. This appeases governments, just for the reason you mention "based on their currences".
...but Libra is designs that they can move away from them over time. It can move to revenue generating investments, like corporate bonds (like money markets do).
Libra can then wait until closer to countries defaulting on their national debt. The countries then start money printing at far higher rates. Their currencies drop in value (aka far higher inflation rates). Libra then shifts to corporate bonds and revenue generating assets.
This is good for citizens. It moves Libra from unsound money (USD + Yen + EURs) to sound money (asset backed & revenue generating assets). That makes Libra more powerful than bitcoin.
This becomes a strategic problem because it can cause a RUN on the national fiat currency, as Libra flees it. Libra then is infitely better than national's fiat currency, because Libra is asset backed. The US Dollar has about $0.03 worth of gold backing per $1.00 (after all of the money printing).
But it is designed so they can switch those out for Gov bonds, corporate bonds, real estate (REITs), etc.
Libra is an idea AND a political entity, which feels like some mixture of status quo and new world which makes me uncomfortable.
What are the advantages of libra compared to a normal bank transfer inside the bank union? Almost all positive aspects of libra already exists in the eurozone thanks to SEPA.
From an american perspective libra seems like an improvement, but the US is decades behind compared to the rest of the world when it comes to banking.