This is a strange reply given that sibling comment points out it's only 2 out of 10 benchmarks where this is allowed because all languages end up calling out to the same libraries.

Even if you prohibit PCRE2, the .NET submissions using out-of-box Regex engine end up being about 4 times faster than Java.

Surprisingly, even though .NET's BigInteger is known for its inefficiency, it ends up being more memory efficient and marginally faster at pidigits than a Java submission that does not use GMP. The implementations are not line-by-line equivalent so may not be perfectly representative of performance of each BigInt implementation.

My point being - if you look at the submissions closer, the data gives much clearer picture and only supports the argument that C# is a very usable language for solving the tasks one would usually reach for C, C++ or Rust instead.