The 1.5-3.5% credit card processing fee for starters. Also, you can't use a CC to send money peer-to-peer globally at near-zero cost.
Compared to... 1 dollar, no, 15 dollars, no, 5 dollars, no, 65 dollars, no, ... transaction fees for Bitcoin.
And of course there other payment systems around the world that don't rely on card transactions.
And don't forget that the entire lightning thing is dependent on banks aka nodes with large sums of money to provide liquidity in the system.
Each problem that's dismissed out of hand by crypto proponents is compounded by the endless streams of bigger and worse problems.
How is building a competing chain to more efficiently solve a problem (high transaction fees) in a competitive market in any way "dismissing" that problem? That seems the exact opposite of dismissing a problem.
Do those new solutions come with new problems? Sure, that's true of any technology. Dynamo-based databases solved high availability and network partitionability of data but come with several trade-offs. That doesn't mean you shouldn't use Cassandra for anything.
That said, Solana is not the hill I'm willing to die on and it's hot garbage. Hedera seems good though.