That depends on whether any actual allocations take place - looking at the C# code samples in the article, the only ones that would cause allocations would be the ones that used Linq. And Linq is kind of verboten in performance sensitive code; I assume the author used Linq in a few samples precisely because they would cause allocations to demonstrate the perf disadvantage.

With the advent of Span, stackalloc and the like, there has been something of a "war on allocations" in .NET recently - it's great to see some extra focus on performance!