“With nodes across Europe, Setl’s network operates using a series of ‘linked’ blockchains that communicate via a so-called ‘witness node’. Back when Setl was announced in July, it was handling 5,000 transactions per second in tests, which amounts to 432 million a day.” – URL
Doesn’t matter. You can settle a gazillion transactions per second in a centralized system, it’s still not secure. If even one node is hacked the system is compromised. And node’s can be hacked, secrets leak, greed corrupts etc.