Is his interest rate example correct?

> In 2020, the 10-year US treasury note yielded 0.5-0.7% per year. In 2023, it was between 4-5% – and 4%. These bonds pay interest every 6 months and return the principal amount invested in 10 years. Here’s how much money every $1,000 invested would yield:

And then he goes on to show that $1000 invested at a 4-5% interest rate would yield either $400 or $500 after 10 years.

But I thought that US treasuries, bonds and similar investments yield compound interest? Or was I mistaken all this time and it's been simple interest all along.